Welcome to the Q&A Forum

When you finally get your urls sorted out, google will sort it out also. in the mean time you may loose ranking, but in the end all will be sorted.

why are they redirecting back to home page? do you redirect them or are you still infected?

I would make sure they 404

I agree with chris, if its not needed why have it?

As for doing harm, Duane Forester from Bing advised not to do it, and said that sites that misuse the canonical tag, Bing will ignore them all together.

There is also the line of thought, that we know that canonical tags do not pass all link juice, just like 301's or any request, there is a certain amount of decay, 15% in the original google algorithm.

It just may be that when you have a canonical back to yourself, it is followed and that you get that decay unnecessarily

I see it like this, its a bad experience to find that a item is out of stock, the 404 will remove you from the index.
A site where you have a lot of products is probably not be ranking well for ever product page anyhow, I would be getting category pages to rank. and not be worried about a few lowly product pages

Somewhere in your site, you probably have a links pointing to both www and non www or moz would not have found both, fix those links and your problem should go away

Probably not, you have only a handful of post and this is not a problem as far as duplicate content goes.
if you want them all to rank, then don't canonical them a only one will rank, try adding a paragraph of unique text to each.

From a purely PageRank perspective. To get your homepage to rank the best, you need to link to every page from your home page, and link back to the home page from every page., but do not cross link between sub pages.

Now that will amass the most PageRank on your homepage, but will not be very good for users, but that is the best starting point read http://thatsit.com.au/seo/tutorials/a-simple-explanation-of-pagerank for good explanation

use this calculator to test what I suggest http://www.webworkshop.net/pagerank_calculator.php

We all have them, no don't worry, google would have ignored them long ago.

Canonical pages don't have to be the same.

it will merge the content to look like one page.

Good luck

Ok if you use follow, that will be ok. but I would be looking at canonical or next previous first

That's correct.

you wont rank for duplicate pages, but unless most of your site is duplicate you wont be penalized

There is nothing wrong with having duplicate content. It becomes a problem when you have a site that is all or almost all duplicate or thin content.

Having a page that is on every other competitors site will not harm you, you just may not rank for it.

but no indexing can cause lose of link juice as all links pointing to non indexed pages waste there link juice. Using noindex,follow will return most of this, but still there in no need to no-index

If you no index, I don't think Next Previous will have any affect.

If they are different then and if the keywords are all important why no-index?

Yes that's correct, or even on the same hosting account

Remember that if you no-index pages, any link you have on your site pointing to those pages is wasting its link juice.

This looks like a job for Canonical tag

you wont find pages on the back end, pages are on the front end,

Can you give us same sample links, thanks

Why build it with Ajax, ajax is good for functionally that needs to load seamlessly but not good for content.
Using escaped fragment seems to not work well as many are having problems getting indexed.

Does your content have to be loaded via ajax? why not load it on the page? would be much simpler

Is this the same website with just a change of domain name?

what sort of web server do you have, iis(Microsoft) or Linux?

No it has no affect.

Yes.

you don't need both sets of files.

before the request reaches your pages, it is intercepted by the webserver and checks for any 301 rules. if it finds one for that url it will redirect, even if neither of the files exist. this all happens early in the request life cycle.

But as I said before, make things easy for yourself, only 301 the pages that had external links