I was under the impression that they continued to live with her after her return, but I never heard what happened to the guardianship.
I could be wrong about part of this or even all of this. I only know what I read on the major news sites.
As to Blanket's biological heritage, I have no idea, but his eyes are like young Michael's & his dark coloring kind of fits too. Either way it doesn't matter. They're all his kids in all ways that matter.