no real idea what is meant by puzzles, the OS games dont have a lot of them, unless you mean the path of blood in 2, i guess that coutns as a puzzle, but you can skip the puzzle part by talking to NPCs some more.
Finding companions is somehting well have to see how they do it. Sven said he wants to focus on the party and as a multiplayer part wehre everyone is a relevant character.

The question is if companions will fill the "Origins" that oculd be played by PCs or not. In OS2 this is the case, in BG it would feel strange tbh.
But if this is th ecas,e then it is required for the NPCs to be there from the start.

Epic levels is... eh.
DnD kind of falls apart at epic levels.
If anyhting, leave it to an expansion, MOTB did high level stuff pretty well but i think it did that because it was a large expansion and you had almost an entire game in which you started from a prety high level already