Answer to first question might be to use cascading combos if you want to see a B list that depends on what was chosen in A. The parent and child records need at least one factor in common. So if you were to pick a lens from the list, it's filter thread size data would dictate what filters you could choose because the filter list would also have thread size. I don't know if that helps with the adaptor issue or not.
I've dabbled in photography over the years, teaching and professional wedding photography and the like but can't imagine worrying about such details in such great depth. Sure, I'd record settings and filtration in the field but can't imagine why I'd care what thread size the 85B filter was for the shot or what mount the lens was, especially since if I used a Canon, it obviously wasn't a Nikon mount.
When you post in more than one forum please provide a link in both threads to the other.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.