Here we go again... 1.) As was stated earlier - banter might be bugged and might get get fixed soon. As I said many times before - it makes sense to hear that banter if you decide to run both romances at once. Also I it is very suggestive, considering it occurs instantly after you've spent night together and obviously it wasn't only "swimming action".
2.) Drow convo. Shadowheart says her line always after you initate and ask if your lover is up for it("If YOU are comfortable sharing, so am I..."), unless you are first time there and you decided to "play fool"(there is an option for her to say this first if you chose dumb responces, like: "What do you want from my lover", or something liek that, can't recall correctly.). Disapproval is the huge thing here aswell and should be fixed asap imo(because it only occurs if you are with Halsin, if you are as 4 and decide to not do it - you don't get any disapproval). Scene itself is rather questionable aswell, but it can be fixed easily for those who dislike "that" fetish without affecting those who do. There was a suggestion in discord to put additional dialogue option that won't require any voice acting. Basically add another dialogue choice after Halsin's line :
"To watch a woman flush with pleasure is one of nature's sweetest gifts... though perhaps you will prove even sweeter, Shadowheart".
Something like: 1. Go for Shadowheart 2. Go for Halsin 3. Remain and watch Obviously Shadowheart's lines about "dreams about Halsin" cannot be fixed without additional voice acting and rewriting, but they are, obviously, questionable and probably in need of fixes eventually. Also it might be better to just lock Halsin's self insert behind active romance with him.
3.) Mizora cheat. I think overall her reaction is fine. She is still jealous and expresses that at the start of the dialogue when she talks to Mizora first. Considering her insecurity in 3rd act, I think her response is fine("Swan..." and her last line does it for me). That being said, some disapproval would't hurt and would add some immersion I guess("Wyll disapproves...Wyll disapproves").
4.) Insecurity. Obviously she is insecure about relationship and it shows all the time throughout 3rd act. 1 time she gets confident during last battle, but that makes perfect sense, because you have to be confident there, there is no hesitation and doubt, you need as high spirit as you can. Insecurity and hesitation is 50% of loss. And it kinda makes sense in the epilogue scene for her back to her "normal" attitude. Also you can see how relieved she is when you tell her that you are with her. Also yes, at worst she "will be waiting and easy to find"(Don't do this to her though).