I think I burned it down . . .

Steven Kruger, plays Coach Ben, states in an interview with TV Insider (you can find it on YT) he thinks that Coach Ben did light the cabin on fire. He said it’s something that will probably never be fully resolved on camera.
But he was friends with someone who was high up on the show and when they talked about the arc/fate of Ben in season 3 Steven was left with the distinct impression that Coach did light the fire. 🔥