Hey, Thank You!
I've just tried it on J320F and it works well so far.
But, since there are different J320F firmwares, I guess it doesn't mean it will work on every j320F. Mine firmware was J320FXXU0APG2.
Of course there are those 2 bugs for now. Hope You can fix them in future.
Anyway nice work man.
EDIT: As I as a beginner delve deeper in Android,
I realized those are not exactly bugs in a true sense, because they can be undoed by reverting changes that are done, changing back resolution and bringing back Gallery.