The lines for Astarion's dock scene have been in the game for a while. I can't find the original yt video that showed them (someone will probably swoop in with the date soon) but iirc the audio files have been in there since patch 5. So they were probably recorded along with the epilogue.
If you want to talk about favouritism, Shadowheart just got another set of camp animations after having her stool upgraded (which I still steal to sit with Gale in act 2) while Gale and Wyll are the only companions left with only their original idles. (Edit: Which is not supposed to sound as salty as it does, I rather they do things they feel motivated to do, than add things they don't really care about to to fill a quota.)
