Ha, you're right. I wonder if it's feasible to get all 10 in a single run. Everything but DING! Max! is easy enough in Hobbler's Hold, but to do all 10 probably requires going into Venture Cave with a Berserker or Rogue and hoping for the right boss.
Anyway, back to the bug reports. If you summon Yin and Yang with WONAFYT, then kill them, the northern wall will be destroyed and your reward will appear. If you then proceed to walk into their original lair, the wall will close behind you and you will be
completely trapped; as far as I can tell, the only way out is to surrender. Seems to me that if they're already dead, the trap shouldn't activate.