They've apparently fixed the remapping issue, so hopefully any other issue will be fixed soon as well. I just find all the mini-games rather underwhelming, gonna play them in co-op later today so we'll see if that livens up the whole thing. At least they're easy enough to complete for some neat prizes.
I tend to make sure that the enemies are all dealt with before trying out a challenge in any area. Just in case they don't disappear for the challenge. I do agree that the build of the shooting stand in general is more annoying than anything. Haven't tried out with Amber yet since I don't use her very often, but I can give it a go with her.
I've gotten all of Noelle's endings and one for Chongyun. Saving the rest for after the event with things to do a dried up again.