How did they do it in BG2? I think that there needs to be a proximity where the other player gets forced to see dialogue. Or at least ask a player if they want to be forced into others dialogues. Choices also need to be seen because seeing what choice was selected before it was selected and not afterwards makes it cohesive. A player may not have even read the choice before it was selected, so it would stay on top of the reply.

How many players can there be for max co-op?

I am SO excited for this game like back when I played Fallout 2. I think about it even when I am not playing it. PC Gaming is back!!!