8ab4e954a0f235f61fad46cd2152d5b3 is the MD5 of my media.zip
Ok, that looks to be the same - this is one problem down!
Next step: might I suggest deleting the install (it won't delete your saves as these are stored down in ux0:data) and install the apk fresh off of VitaDB or from here. Then unzip Media.zip and install that into the game folder as instructed.
Stray thought: what plugins might you be using on your Vita? There are some combinations of plugins that the Unity engine simply won't play nice with, and I've no way of debugging or troubleshooting this so it's a problem that cannot be solved I'm afraid.
At this stage I've got no idea if any of those plugins could be causing issues. My best suggestion would be to ask around and see if someone can give you a copy of the vpk that's already had the media.zip put into it - we've tried everything else that I can think of, and if a known good vpk doesn't work then you'd need to address the plugins by turning them off one by one, but it shouldn't be nonpdrm or kubridge at least