So since Yuu looted all abilities, including Yusa's of course, does that mean he can be possessed by someone just like her? And if so, can that person be Kumagami?
Yusa has the ability of Spiritism. She is understood to be a medium, seemingly capable of channeling and/or conversing with the dead.
So it is not entirely impossible so long as they have a way to communicate with Kumogami's soul.