Fair enough. In the case that the products are more or less identical, it would help to have naming aliases in the other groupings that all point back to a single entry. This would at least help other people find it if they have an old/differently labeled tin. Also, it may be helpful to have a "version" or "edition" field so that people that want to track the specific one rated could do so and it would be something searchable/sortable outside of just typing it into the review text. Regardless, thank you for the helpful information on the pedigree of these particular blends. Definitely an interesting history!
It'd be impossible because you'd have to go through thousands of entries and try to sort it all out. You can't ask the reviewers who originally posted them because there's likely no contact info for them, and who knows how many of them no longer have accounts.