Hi jscris. I don't know anything about your first issue, but you can search if it is already reported in
https://github.com/koreader/koreader/issues
Regarding your 2nd issue. I made the change based on a user request. See what the change does
here. The Pull request itself is
here.
Sadly android is hard to do right from KOReader POV, so any help to make this option (disable touch with a hw key) switchable would be awesome.
Your 3rd option cannot be fixed as KOReader does not control screensaver behaviour on Android and won't be able to do it.