Hi! Thanks for this feedback!
1. Seems we indeed broke something with Yun, and we are currently looking into it.
2. Could be the case, yes, since we had to change the trigger for Zahera's route it might've clashed with the older save.
3. You could try pressing ignore on that error, sometimes it let's you continue playing, but if the error persists, you can send us your save file and we will try to find the root of the problem.
4. Did you finish any further content with Andre, or did you get stuck on the pool scene for Andre? She's supposed to have a lot more content after the pool scene!
5. A few months ago we decided to swap X-Ray for a different system, and while it's still in development, it made little sense to further spend our resources on adding new X-Rays just to remove them later on. With Seraphina, Part 1 we presented new cool side content with girls sending you nudes, which should be better and opens up more ways for us to keep adding content to characters whose story is already finished. In the coming months we will add even more nudes, and will remove X-Ray system entirelly.