With it being multiple roms, across the full version and beta version, having the demo version work (does it still work?), and not having the special exceptions on, I am afraid I am all out of ideas.
Hopefully someone with more knowldge will be able to help. I do know that while your phone has an unspectacular processor and gpu it is more then enough to run 3d games on drastic let alone Phoenix Wright. Also while 1.5GB of ram is enough there as well. I worry about the 8GB of space but I am assuming that you are not running out of internal memory. Unless there is some odd thing about that phone's configuration that causes issues it should work fine.