I think you are confused. Mia is dead, but because she's a spirit and her family are all mediums, she can possess them temporarily. And when she does, for some reason, they all transform to look like her, which include her massive tracks of lands.

Normal Maya

Mia maya

And yeah, it even works on 10yo Pearl, which is pretty weird.

(yeah, I had to retype this several times because images don't fucking work)

"I breast my case"