If I were you I wouldn't even bother with split screen (but I am talking about the "couch coop" style multiplayer, one device with a big screen and multiple controllers), just zoom in/out dynamically so all players can be seen on the same screen. Kinda like in Zombie Estate 2.
I'll have to look into it. Once the jam rating is over, I'm going to add some features that got missed due to time / I totally spaced and forgot about. Not sure how this would look zoomed right out, but love the idea.