It depends a lot on how well insulated the place is, ceiling height, air flow, etc. Obviously, in a perfect world, the heat would come from the floor, like radiant in-floor heat, but ceiling mounted can work. Our mini-split heat pumps output about 8' from the floor and work fine, but our house is very well insulated, and we are in a mild(er) climate.

I grew up in a house that had heat vents in the ceiling in some rooms, and vents in the floor in others. So considering the same level of insulation; the only difference I noticed was more air movement when the forced air came on with the ceiling vents.

i think I'd want ceiling fans that would then move the warm air down and around.

Steph has a good idea there, the fans that can be reversed would push the air down along the walls and would not make you feel cool because they would not create a breeze. I also wonder where the cold air returns are. If they are at floor level, maybe they help pull some of the warmer air down, but not as well as a fan on reverse would do.