Not sure, the only game I played before BG3 was Dark Alliance 2 on PS2 around 20 years ago. Well that and homebrew 3.5e/5e tabletop, but that obviously was unrelated story-wise.
Other than Jaheira, almost all of the connective tissue is found in Act 3, but that makes sense, because it takes place in the titular city. There are at least two characters in Act 3 that are not in your party that return from previous games.
spoiler
One is in the Shar temple, and one is in the Bhaal temple.
Not sure, the only game I played before BG3 was Dark Alliance 2 on PS2 around 20 years ago. Well that and homebrew 3.5e/5e tabletop, but that obviously was unrelated story-wise.
Other than Jaheira, almost all of the connective tissue is found in Act 3, but that makes sense, because it takes place in the titular city. There are at least two characters in Act 3 that are not in your party that return from previous games.
spoiler
One is in the Shar temple, and one is in the Bhaal temple.