This is really specific, but here goes:
I’m thinking it would be neat to include an item like the Master Key introduced in Fire Emblem Shadow Dragon. The obvious way to do this, it seems, would be to create an additional item set with the “Lockpick” functionality that anybody can use.
However, I don’t know precisely how the “Thief Skill” Lockpick lock is set up. What I’m hoping is that the “Lockpick ItemID” sets that specific item to be locked to only units with the Thief Skill ability flag, while other items set to have use effect 0x20 (Lockpick functionality) would in theory be usable by anybody.
I’m asking here to verify how it works, because I don’t wanna do anything needlessly-complex if I don’t have to, and having a Master Key isn’t really that important, anyway; it’s really just on my “absolutely non-essential but it would be neat” feature list.