Responses
I think og hikaru's soul is eaten by unuki-san. That's why unuki-san can grant hikaru's wish(Unuki has to do something before he grant someone's wish).
Because in the last ch unuki-san want to eat yoshiki's soul to grant yoshiki's wish, but he can't(the item protected yoshiki from unuki).
Sorry for the bad english, not my first language

do you think it's possible that og hikaru's soul still 'exists' inside the hole dimension? do we know if the soul of the body nonunki-san possesses completely disappears or no?
(i feel like this will either be debunked or strongly supported by what happens to the girl in the next few chapters)