As background I have played Icewind Dale, Baldur's Gate, all the Diablos, all the Fallouts, Skyrim and several other games. I am now playing my fifth time through this game and each time it has been different, it is determined by the character you create and your interactions with your companions. The quests for your companions don't trigger if they are not in your party or you don't talk about it with them. So each time it has been different. I did not notice that Serafin was gay and that is probably because I was not looking for it, and it wouldn't matter if he was. If that bothers you don't have him in your party. There are places that you have to make ethical decisions and what you choose will determine what happens later in the game.
All the games I mentioned earlier, I have not played them five times. Skyrim was three times and Diablo 3 was four times (but that was because there were no other new RPGs).