You can check by grabbing the first paragraph of text from a product page and Googling it. Different pages may return different results - the example I looked at returned the variations I showed. Another didn't (maybe Google hasn't indexed the variations of these yet), but did return the same copy used by another website.
Go through analytics and find your pages that have dropped the most and go through this process and you'll eventually see a pattern of issues (the content being presented on multiple URLs).
No idea about the review feature with Cubec, never used the CMS. But have resolved similar issues via WMT / redirects as outlined above.
It'll take a while to notice any impact of changes - you need to wait for Google to reindex the pages first. But your traffic logs should show some improvement if you make the changes.
I understand your use of different spellings, but to be honest I think you can pick one style and run with it. Google should be able to handle it and rank the page for appropriate terms. It's like optimisation vs optimization - personally I'd go with whatever is your local spelling. Going off on a tangent and possibly a different discussion, but I think you need to weigh up user experience vs SEO on this one. It may have been the case in the past that SEO won out, but I think nowadays UE is more important. Personal opinion of course, but might be worth testing and see how your conversions going when all the tech stuff is sorted out. :)