I'm just going to wait and see on this one... Won't be surprised on some characters (IF they return), especially given a certain comic around the same timeframe (thanks Flesh to Stone/Stone to Flesh). I can easily see Viconia and Hexxat returning... As for Edwin/Edwina.... Didn't Elminster take Edwin's magic away in his ending?
I only wish BG3 could acknowledge that the protagonist from 1 and 2 has become a god, ideally whose alignment is of the player choosing (through parsing a ToB final save or otherwise), determining the god's portfolio. But they're just going to pick the official Abdel Adrian story which isn't very interesting IMO.
Knowing this, I care not about meeting Adrian's companions, since they are not that of any of my BG1&2 characters.
Thinking about it, it could have been fun to play as a priest of <CHARNAME> instead of the usual Helm/Lathander/Torm/Whatever. The Illithids might remember fondly meeting this <CHARNAME> a couple times back in the day :D
-she will also be exist in every Baldur's Gate Game :D
-If she is able to join party (in later game ofcourse she should be in a very high level after BG2), it is also good because she is multi-class fighter-druid (tank and caster/healer) will be usefull in a 4 man party. (As i know Baldur's Gate 3 will be limited to 4 party members)
I really want to see Viconia, she was my favorite companion and the one who always agreed with my actions, I also loved her as a character. Remember that the game is set a hundred years after Baldur's Gate 2 so there are only a few characters that can still be alive