Complexity is getting out of control ;)
I guess this can never be productized... beh...

I morphed a big spike into M4's head and let a magnet fly through it. It seems to leave the morph untouched. So magnets in general seem to be applied before-morph. That would be best for me. But maybe the figures are set up even differently. I parented the magnet to the head. But maybe if its a bodypart in figures... who knows.

Then i lowered the magnet to touch the unmorphed head surface and the spike began to deform. The heavily deformed spike I exported, morphed  and back loaded the semi-magnetized morph. Script told me it could that with acceptable precision, and it basically looked exactly like the deformed object. So Figure + Magnet + Morph = Deformed .OBJ. Correct =)

So that leaves some hope... will need more testing >_<