I'm not trying to sound mean, but you're kinda asking for the impossible. If you don't want to use shoes, climb it barefoot. If you don't want to leave marks on the wall, then you need to pull yourself up without touching the wall with your feet, and that requires some conditioning related to the Muscle Up. If you're looking for "fun" then try a mega kong.
You pretty much mentioned all your choice above, so pick one and work on it. I hope I didn't offend you in any way, just trying to put reality in front of your face.
I hope you find the best way.
