Does the masking AI not work on your iPad? It works perfectly fine on mine. Also works on my iPhone even. It doesn't seem to do the people selections with multiple people though and perhaps that is what you are looking for?
But I was talking about the Masking AI they introduced in last october desktop release, that allows you to select and create mask for eyes, mouth, teeth, and many things, in just one click. It's really powerful, and can't wait to see this feature on Ipad.