I think the romance option starts too forced, you barely know anyone and out of nowhere .... Would you like to spend the night with me? and all companions comment you are realy close... Ehmm did i miss something ?
We'll Astarion is the only one really like this and it fits the character perfectly. Shadowheart really just wants to talk to the PC which is the equivalent of flirt (+kiss which is optional) if you ask me.
The dialoge changes a lot depending in whom you speak to first - I agree though if you first talk to Astarion and accept his advances everyone will come accross as a molester.
