larian did pretty well in the relationship progressions in previous games so I am assuming they'll have something in mind for this game as well. I turned down the Vampyre and went to bed alone but I reloaded this scene several times to see outcomes approaching different party members first and not everyone wants to bang you if you don't talk to Asterion first. You get very different responses depending on who you talk to first.
Interesting. I didn't reload for all of them, but I did talk to Astarion first, then Shadowheart first and in both situations all of the party members had a comment to make. Then there was Lae'zel, who I had basically stationed at camp since my PC is a fighter and never talked to her, was grumbly that she didn't get to bang me.