Yes, I do think the signatures belong to the same person, they may not be as uniform as you expect them to be, but that is probably due to the fact he was signing a recently adopted name.
He was a Jamaican man named Barrington H Smith, iirc.
Yes, now look at the B of the known Barack Obama signatures and what his signature looks like and they are not even close by a million miles. I don’t believe there is any way that Barack Obama signed those as Bari Shabazz. Until someone shows me otherwise I’m considering the Bari Shabazz trail as a wild goose chase.