Personal opinion. I think that Tav is a descendant of Charname from BG1-2. Of course that is pretty low hanging fruit, so I am probably wrong.
I think it should totally be possible to roleplay Tav as a descendant of Gorion’s Ward, and this sounds to me like a fun option for Larian to chuck in a small number of dialogue options to support for those players who’d like to to go that route, to make it feel a bit more real in the game.
I’d very much hope that Larian don’t actually force any particular heritage on our custom Tavs, though. Personally I’d want as much freedom as possible to determine their age (eg some of my BG3 character concepts would be older than Charname) and race relative to any particular BG1/2 world (eg to play a half-Orc Tav when I’m assuming Gorion’s Ward was an elf). Quite apart from wanting to be able to determine their personal history for myself.
