1) I will wait for more updates before play it again to play it with more content and give you a better and more complete rate.
2) If you need a good VA I recomend Misuzugon, she have a very sexy voice and have packs with moans, maybe this help you to advance more and better with the "Audio Messages".
3) Maybe I need play more and try play better with the options but like I said before is better wait for more updates.
4) I was thinking in what you said before of 2 more girls and since you will do one NTR profile more and the other will be NTS, maybe the second NTR girl can start being NTS and become after in NTR to be a middle point between the first profile and the third profile (And you can make a choice to let the player decide if want continue with the NTS form or become it in a NTR story)
For example: The girl ask to the MC (Player) if want continue or not with the NTS experience if he want continue with the NTS the story will continue being NTS but if he ask her to stop the story will become in NTR (The girl want continue with the new experience even if her boyfriend/Husband don't want it)
I hope this inspire you and help you to improve the game (And to please the more type of public possible)