hey I just said it was weird he was the only one who doesn’t leave "corpse".

Yup. I'm just expanding on that. I didn't mean to imply that you agreed with this theory.

As we discussed before, all demi-gods except Mohg leave some sort of "corpse" after they are defeated... I'm just expanding that to say all demi-gods including Mohg have a corpse... thats Mohg's "corpse" in the egg.

In his cutscene he grabs the hand and says that’s Miquella so that’s pretty much confirm the one in the cocoon is Miquella.

I believe that this projection of Mohg is confused. He think's Miquella is in the egg, but thats not Miquella. Miquella tricked him, he's kissing his own "real" hand.