Is there a MusicBee app?
MusicBee is not available for Android but there are plenty of alternatives with similar functionality. The best Android alternative is foobar2000, which is free.
How do I reset my MusicBee library?
Click on the MusicBee in the top left corner and go to File>Library and click on Create New Library. Choose where to save this and remember it. Now go to File>Library>Open Library and look at your available libraries. One is the new one, the other(s) should be the ones you want to delete.
Is MediaMonkey still supported?
The current version of MediaMonkey for Windows is 5.
https://www.youtube.com/watch?v=JKW10EZuHK4