[mdp]

@EldRick:
For FBReader (can't do without), I install a repackaging changing the manifest
(the 'package' attribute of the 'manifest' tag and the 'android:label' attribute of the 'application' tag... )
One could note, this is what Onyx should have done!
Incidentally: I would use my own hacking of FBReader anyway, because I want two columns also on portrait.

Fonts, I use plenty - each application (I do not know about the Onyx ones) has its own way to use more...
You would create a folder populated with fonts and specify it in your application preferences, or some applications have their own fonts folder

Converting .otf to .ttf should be quite easy... I was considering it earlier to try Google's Literata