I was at worlds of fun and we were telling my cousin from Texas about the mamba. He asked if it was a short ride and before I could say anything some kid said it was the longest coaster in the world and it lasts about 6 minutes!
It would make sense but I'm pretty sure that is a track for a wing coaster and I doubt that cedar fair would give that to us. Also it wouldn't fit our park that well.
I think for sure a coaster is counted out but getting a dark ride seems likely with all the work being done at the buildings near Timberwolf. I really don't know much about haunt so I can't help you there.
On Monday its dead I went last week and every ride was a walk on. Since your staying to closing it might pick up a little bit once OOF closes. But it should still not be that busy.