Hi Bob,
Although not the answer you want, it depends!
What I would do, is split test your outreach.
In one email, make the offer right away, and in another be a little more cautious.
To some extent, it does depend on what you are asking the bloggers to do. For example, are you asking them to write a review of the PDF? or do you want to write & supply a guest post?
In either instance, I wouldn't offer them the link back from another related site - that's just me personally. To me, that would look too much like one of the '3 way link swap' emails that I delete each week.
Offering the adwords traffic is an interesting one, however I would use that one as a contest personally - one of the reviewers picked at random.
In terms of offering a FB like or Tweet - I would instead tell them that you would be happy to share their post across your company's social channels.
The actual email you write, including the subject line, will depend to some extent on the tone of voice of the blogger you are reaching out to.
Re: Buzzstream
I have used Buzzstream a fair bit myself - what I tend to do is NOT use their inbuilt scraper (I don't like most serp scrapers!).
Instead I use the bookmarklet they provide, which then allows me to make notes (on the final page of the bookmarklet, after confirming their contact data etc), on things like: Their tone of voice, links to their guest post guidelines, any notes on if they do giveaways, etc.
Also, when first adding the prospect to buzzstream, be SURE to use tags that will be useful in the future (may be useful for other campaigns/clients etc). Doing things like using non-industry specific tags like 'giveaway' or 'contest' can help with future efforts, as you can search buzzstream for such prospects.
One other advantage of using buzzstream, is that if you do create 2 different templates for the emails, Buzzstream will try to automatically record the response rate as a percentage...
For the above reason, consider just bookmarking a set number first, say 10 to 20% of the total number of blogs you intend to reach out to, **but **ensuring you have enough sample data to be reliable. - The more folks you intend to reach out to, the lower the % can be, basically!
Then, before you launch the campaign in full, check the response rate of each of the respective email templates, and go with the one that had the best response 
This way, you are testing the water, and getting some stats (other than opinions) to base your campaign on. I like this method, as no 2 industries are the same really.