The Forms MIB takes by Jason Williams

I've got a random theory that I don't know if anyone else has come up with yet regarding the different shapes that MIB can take.

Over the years we've seen him take the forms of Christian, Yemi, Isabella, Alex Rousseau, Locke and of course, himself. What do all these bodies have in common? As far as I can tell, with the exception of Isabella, none of their bodies were buried at the time there forms were taken over.

Christian - casket on the Oceanic 815
Yemi - drug dealer's plane
Alex - New Otherton
Locke - case
himself - "Adam" in the caves

Of course, MIB doesn't take over the old body, he forms his smokey self into a duplicate (we know this as his own body was left by Jacob in the caves and Ilana was carrying around Locke's body in the case). Anyway, I digress...

If you remember in the Season 5 episode "LaFleur", when Sawyer and Juliet saved Amy from the Others, she freaked out saying that they "We have to bury them...We have to! The truce. Oh, God. We have to bury them. And we have to bring him back home. We have to bring Paul back with us. Please. Please."

I think the Other's knew that MIB could only take the form of bodies left above ground so that's why they made sure that in the truce with the Dharma Initiative that old bodies had to be buried.

I could be wrong on this one and it doesn't really matter in the big scheme of things...of course my only problem is that Isabella "shouldn't" have been on the Black Rock for her body to end up on the Island. Though one could argue that in the "off Island" world, they took Richard away from his house and left her body there unburied. But this would mean MIB could make contact off the Island which I don't think he can.

Any thoughts?