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"Natural" is the key phrase in your question.  100 links from a site typically isn't natural, but it may be.  Considerations include:

1.  Is the site relevant to your site?

2. Is the site "alive" with lots of activity, and not abandoned.  Often bot spam hits abandoned sites, including EDU sites where nobody is monitoring them for spam or replying to comments.

3. Is the site an authority site within your niche?

4. Does it have suspicious external linking patterns (Penguin spammy stuff)?

5. What kind of links do you have?

• Are they exact match keyword phrases used instead of your name when commenting on a blog post - if so, this is spam and 100 of them will hurt you.

• If they are legit blog comments and engagement scattered among high authority blog posts using your name without stuffing keywords, then it might be "natural."

• Are they footer links on an unrelated website that has over 100 pages?  (web designer tactic) Might hurt rather than help

• Or did a niche authority site decide to add your awesome site as a resource in their sidebar?  Likely to help, not hurt

• Is it coming from paid advertorial links?  Bad.

These are just some examples.  Unfortunately, there is not a straight forward answer as there are a lot of variable to consider.  However, if you use these considerations, usually you can answer the question of whether or not the links are helpful links or hurtful links.

If you dive into Google Analytics/ GWT, you can get some great information like this - and it's free.  Not sure the exact reason you want to follow specific individual behavior, but if you are trying to gather more intel on how "hot"  your prospect is, then you may want to consider looking into marketing automation software.  These are designed to track individuals and score them.  They can even integrate them into your CRM like Salesforce.

Do a search for marketing automation software.  Here are a few to consider, from low cost to higher cost, higher functionality:  Optify, Act-On, Hubspot, Marketo.

Agree with Cesar, your backlinking profile looks a bit suspicious.

Here is a detailed article that still might be applicable to your situation: http://www.seomoz.org/blog/lifting-a-manual-penalty-given-by-google-personal-experience

This article has some great tips that everyone can benefit from in prevention too.

While these aren't likely tied to your ranking drops since Penguin 2.0, here are some things that you should look at improving to help your site too:

1. Site design needs to be fixed - content fits screen, but still allows horizontal scrolling
2. Not mobile responsive or mobile ready
3. Add Google Authorship and Publisher

Hope this helps.

Couple of resources to check out:

http://yoast.com/footer-design-by-links/

http://www.seomoz.org/blog/lifting-a-manual-penalty-given-by-google-personal-experience

http://www.weidert.com/whole_brain_marketing_blog/bid/114916/6-Surefire-Ways-to-Piss-Off-Google-Penguin-Tarnish-Your-SEO

First issue is regarding links to domain ratio.  Do a quick audit of the top 10 competitors for any of your terms.  Run them through majestic and see what their ratio is.  It will always be a multiple.  The ratio isn't as much a problem as the source.  For instance, if you are active on an authority blog within your niche, you might comment on lots of posts.  Since the blog is an authority and there isn't much spam, these are relevant and higher value links than blog spam where someone ran a bot and found spam ready blog networks that will take your links all day long and all of the commenter names are exact match keywords instead of natural looking names.  In this example, the ratio might be the same, but there is a big difference in the SEO impact to your site.

I advise against a footer link attribute back to your site.  This is bad form and it does not add value to your clients or their visitors - all web developers should consider stopping this practice.  As far as SEO goes, I doubt most of your client sites are within your niche , so what signal do you think that is sending.  Using an anchor text about your topic and putting it on a client's site on a different topic doesn't make sense from an SEO standpoint.  Besides footer links and attributes already having low power, adding them to unrelated niche sites is not going to help you in my opinion.  There are plenty of cases of these footer links getting web developers penalized in Penguin over the past 12 months.

Is your objective SEO or self-advertising?  If you are proud of your work and just want the advertising, then use your brand (company name) without a link: "Site design by Company Name."  Let potential clients find you by searching for you name which helps your authority.

Hope this helps.

Agree with Erwan, sounds like you are getting personalized results rather than actual.

1. Use SEMRush and Google Webmaster tools to find keywords you are ranking for (including ones you didn't know you were ranking for)
2. Add any new keywords you are ranking for into SEOMoz to track

You won't be able to use authorship on the 3rd party sites typically, but even if you could, it wouldn't be necessary because the article would have already been attributed to your original blog post.  So, no

As long as you have your authorship set up properly on your primary blog, and you are linking to it, it likely won't hurt your primary blog/ site - unless you get carried away and post it on dozens or hundreds of 3rd party sites.  Make sure it gets indexed on your original site first, before publishing elsewhere.

I understand you may be wanting to keep the blog post in its entirety on the 3rd party sites in order to provide value, but I would recommend that you use really solid summaries/ excerpts and then "click here to read more" type link that takes them to the full article on your main blog.  They will still get the full value, and you will get the extra targeted traffic to your main blog.

I would stay away from a double redirect as the negative signal risk outweighs the benefit, and in this case there is no benefit or reason you would want to do it except for convenience (one less thing you have to do).

If those old domains still have traffic, then you should go in and change their redirect to the new site.

Press Releases are meant to get picked up by lots of media outlets.  That's the point.  For example, if you submit to PR Web, your press release will end up on hundreds of sites.  I know from experience that it does not hurt you as I do daily for my clients and my own sites/ companies.  It helps as long as they are optimized well and have high quality content that people will want to read.  Google et al will select the "best" one(s) to keep in th SERPs and the rest will drift away.  Even though those pages with the press release still exist, they have no impact positively or negatively for you, and you won't get a duplicate content penalty as the search engines knows how to treat News. 
I agree with Chris that you must understand where they fit into your overall strategy.  They are only one small piece of the process.  If you build a strategy relying on press releases, you are going to be losing that treadmill battle.

You should redirect by mapping the pages appropriately.  The old sites seems like you are kind of abandoning it, so whatever rankings it currently has, will likely drop over time and the links will lose value.  As long as you are staying active with the new site, everyone wins - visitors get to an active site that is being updated, instead of an abandoned one.  You win because you are not going to have to worry about the old site or losing that traffic or losing link juice.  The search engines win because when they send traffic to the old URLs, the visitor ends up on a better site with fresh content.

Check this out:

http://searchengineland.com/penguin-4-with-penguin-2-0-generation-spam-fighting-is-now-live-160544

It is official.  I suspect this may be your issue.  Since you have done everything "by the book", your site might not have done anything wrong per say.  Instead, the other sites may have been deemed bigger "authorities."

D is sounding pretty good right now...

You could go either way.  Without knowing how much existing content, traffic and the age and authority of your existing site, I will share my recommendation based on the assumption it doesn't have much authority or traffic.

I would merge and put more effort into one site (option A).  Focus on high quality, high value information for just one site.  As important as content is, dividing your efforts between 2 sites chasing the same keywords would be tough.  Combining your effort and time into one site would allow you to do a much better job.   1 + 1 = 3.

An exception to this recommendation is in the case that both have high authority and traffic, but different voices/ personalities.  But even in this situation, you could merge and turn it into an a big event/ story of how you are getting bigger and bringing the two communities together in order to bring even more value to the table, etc. - this could help get you some extra publicity and traffic from the situation.

It shouldn't hurt unless you are stooping to the low end secondary citation sites and spam directories.  They can hurt you just like any spammy source sites can hurt.

You might be at a point of diminishing returns if you have covered the majority of high authority citation sites, industry-specific sites, and hyperlocal directories (BBB, Chamber, etc).

The best way to make up for "factors such as less reviews" is to start focusing more energy on that.  A diversified strategy is always going to be better than a lopsided one.  I think we all get into a little creative avoidance when it comes to getting more reviews, but it is an important part  and it sounds like it is time for you to put your energies there.

I had the root version with /about or /posts and it was working.  Seems strange why it would have been a problem as it is just a URL hyperlink.  Would be curious too why this occurred.

To answer your last question first, this should not hurt your main content pages that you have optimized.

Without knowing how the site is set-up, there is still benefit in having these dynamically created pages, especially since they contain product details.  Without meta data, the content ("details" you mention) can still be read by the crawlers and the theme can still be determined.  Assuming there are still navigation links back to your main optimized content pages and that they are related, there can be some benefit passed (assuming they are thematically congruent).  So in this situation, the benefit outweighs the risk (assuming I have understood the situation correctly), so I would not block the dynamically created pages.

I would still work with the developer to find a way to push the product name and details to the meta data for the dynamically created pages.

Peter,

Definitely add it to every page, not just the home page.

As John mentioned, aesthetics are important in determining the best locations.  Here are a couple of considerations:

1. Aesthetics and usability (where it will best benefit the visitor while also achieving your goal)
2. Common areas where it will be automatically inserted into each new page, especially in CMS/ blog sites, such as footer or sidebar

Limitations occur when you have a business with multiple locations (more than 2 or 3), as it will start to create aesthetic and space problems for you.  In these situations, you will have to determine the best method on a case by case basis.  For example, if you have a bank with one main location and 10 branches in a metro area.  You may decide to run the main office location schema on the common pages and then use the individual location schema on their specific contact/ location pages.

Hope this helps.