Huh not sure since I'm not a developer (and didn't work on that website dev) but I'd say all of the above^^. If useful, here are their url structure, there's two kind :
- /searchpage.htm?action=search&pagenumber=xx&query=product+otherterms
So I guess they are generated when a user makes a search
paginated (about 15 pages generally),
and I can approximately know how much they are duplicates, I can tell some are probably overlapping when there's a lot of variations for the product. There are just a few complete duplicates (when the product searched is the same with different added terms, doesn't happen a lot in this list).
- /searchpage-searchterm-addedterm-number.htm
Those I find surprising, I don't know if they are pages generated with a fixed url, or if they are rewritten (Haven't looked at the htaccess yet, but I will, god I have a headache just thinking about reading that thing lol)
There's about a thousand of them all (from GGanalytics, about half of each sort, and nearly all are indexed by Google), on a website with about 12 thou total in pages.
Maybe the traffic loss will be compensated by the removed competition between those search pages and the product pages (and the rel=canonical is surely way less brutal than a noindex for that matter), but without experience in these kind of situations it's hard to make a decision...
Really appreciate you guys taking the time to help !