We should replace the hacks (use of ApiCheckCanExecute and mobile frontend hooks) in WikibaseRepo hooks with some mechanism in core for disabling direct editing of content types.
first step is to add the mechanism in core, which is what https://gerrit.wikimedia.org/r/204230 does
then we can remove the ApiCheckCanExecute hook stuff in Wikibase
for mobile, adapt it to use the new mechanism, probably with a method_exists check on ContentHandler, assuming they care about backwards compatibility. then we don't need the SkinMinvera hook code in Wikibase.