Guy would raise a brow a bit apprehensive about summoning ghosts in general but would not voice the matter as much. He would shake his head a little at the mention of possible possession. He would make sure to stay away from the ritual. 

"The sun's rising already? Guess that means the clouds overhead are clearing out too. An unfortunate stop to the down pouring rain."
He'd sigh, before going to the kitchen to clean off his dish as well.
It took less than a blink of an eye for his dish to become sparkly clean. 

"I'll go ahead and take a nap. Make some noise if something happens..."
He would sneak away to a bedroom for a nap. Although would slide furniture to block the door behind him.
In case the magic ritual did go wrong. On a good note, the bedrooms should be relatively clean since Guy had visited them earlier. Nothing removed, just organized and well scrubbed.