First, thanks for organizing this jam. I started working on this last week, but took a break for Ludum Dare. Now i'm back to it!
I was planning on kind of your standard turn based rpg battles. But then I made this grid and put drag and drop controls on the girls. Playing with that idea seems more interesting so I'm thinking that their abilities are somehow tied to the way they move on the grid. And the enemies will probably do some fixed targeting attacks instead, so you can move the girls to avoid them. We'll see! Game dev is all about iteration!