I have the sneaking suspicion that Larian might break with the series' tradition of having a protagonist with a clearly defined background relevant to the game's narrative, and instead give us one with barely any background at all, just so that no one gets to complain again that "the story is too restrictive".
Which, fiy imo, would f***ing suck and I would hate.
I didn't like it in Neverwinter Nights, I didn't like it in D:OS(2). All my favourite RPG's give the protagonist a plot-relevant background. It grows immersion and helps me to properly roleplay. I don't wanna be some random dude with no personal relation to what's going on in the plot. Where usually my character's only logical choice of action would be to get the f out of there. The plot hooks in the original series where brilliant. BG1 gives you the following options: Take revenge for your dad's death, kill the guy who's trying to kill you, figure out your own past, or be the hero. BG2: Safe you sister/soul, get revenge on the guy who kidnapped and tortured you, try to find out what that guy's deal is, or be the hero. Most games just give you the last option which is duuuuuumb.
Anyway, with as little information we already do have, I would assume that Charname2 is gonna be a Baldur's Gate citizen. Maybe a member of the Flaming Fist.
Though highly unlikely, I think it would be hilarious if Charname2 would be one of Coran's kids. But they can't do that, since that would be restricting the racial options. Though maybe maybe maybe Larian takes a slice from DA and let's you choose from a select number of origins, letting you choose who of the old companions is your (grand)parent. I.e. Coran for elves and half-elves, Mazzy for Halflings, Imoen for humans and half-humans, etc. That could be neat.