It worked for all I tried. A calculator, the amazon app store (still wouldn't allow other apps to be installed though, not authorized message), ES file explorer, Terminal, Blackmart (also wouldn't allow installing other apps here). I can't see why it wouldn't work for any app you have an apk for.
I managed to get the P4pro+ V2 controller to take a bunch of apps. I installed pix4d, control+dji, the amazon app store, ES file explorer, Terminal and a couple more. Pix4d was my big priority, so I made a video here:
Our office bought P4 Pro+'s to use for mapping, so I was a little concerned when I heard they wouldn't take pix4d. Happily after spending tons of time on it I managed to figure out a simple way to do it :)
Here's my tutorial: