But yes, ceiling mounting is possible. You just can't find a ceiling bracket with long enough "arms" to reach all these screw holes. So I had to use additional rails and managed it - even on my sloping ceiling.
The feet are screwed in so there are screw holes but I don’t know whether they are meant to hold the entire weight of the projector. I use them to mount it to the wall, which, so far, has been working fine. And yes, the image can be flipped any which way in the settings menu.