I see what you mean about the beaches...I could go with something like the Magi magically raised the land masses from up out of the ocean. One for each of them to 'lord over' and the small one in the middle is neutral ground. Change the texture of the 'beaches' and they could be plateaus or mesas or something.

I'm not sure I'd want to try and put tree trunks on there, but its always a possibility, and something I haven't tried before.

Who knows, I may not even go anywhere with this at all.