Just noticed that they were added to the iOS compatible controller list just no screen support. I guess you can put your iPad over the prime 4 screen 
Putting the iPad on the P4 screen is a fair idea.
Is there an option on djay to have the deck graphics removed from the iPad screen and just have the iPad showing library/playlist/search type info?
Probably could leave it in browser mode. Maybe the M version could be supported also since the rane one is already working with the iOS version.