You need to talk to one of the actual Mal-Valers if you want to understand the theory. My cursory, outside-looking-in grasp of it is as follows. A [non-existent] woman named Anna Toot married Obama Sr and had Obama Jr in February 1961. Later this child died. (I have no idea how much later.)
Meanwhile Malcolm X and Valerie Saruf had a son. Somehow, for reasons only a Mal-Valer could explain, the Malcolm X son was entrusted to the Dunhams to raise, and given the name/identity of the deceased Obama Jr.
I think that’s it in a nutshell. It would be interesting to have an actual Mal-Valer fine tune that overview, but I rather doubt it will happen.
Your post covered every bit of my interest in the theory.