I mostly run D&D 3.5 these days, but the setting is pretty system-agnostic. It started off just as AD&D was launched, then went to 2nd Edition, skipped 3rd & 4th (a lucky escape....), and currently works in 3.5 and 5th Ed. As long as parties using different editions are in different bits of the world and never directly meet, it works fine 😀 But I always make sure that rumours of what each party does reach any others, and what they do can affect each other.
I love the idea of a family heirloom dungeon 😁 Makes me think I should train someone up to run mine after I'm gone so all the work doesn't evaporate.
I've been running Argull for... umm, nearly 44 years on and off, so it's got quite a bit of lore (as well as so many crazy events that have happened to characters). When I pulled out the world map for one party a little while ago, I was asked how old it was. When I told them, one of the girls was "like yeah, that's twice as old as me...."
Also: rambling about D&D is good ! You should set up a game and find some players to dip into that dungeon of yours 😀