Aww, you're too nice ^^ sorry about the delay, but I don't go online much these days, and since I've been missing a few fights here and there I wanted to check them out before getting the results spoiled, so I avoided Sherdog a bit...
1) Well I can tell you that the fight from the first UFC poster was from a draw between Marco Ruas & Fernando Pinduka, in a 1984 "BJJ vs Luta Livre" event at the Gilberto Cardoso gymnasium in Maracana, Rio de Janeiro, Brazil, headlined by a Rei Zulu fight.
The picture was taken from this fight, sorry for the shit quality =>
I think it was probably taken from the second video, toward the end of the fight, specifically during the sequence between 3min & 4min. There are several times during that GnP session where that picture could have been snapped.
There is also a short window in the first video of 10 seconds maybe when they were in a similar position, but it's hard to tell with that quality.
2) When it comes to the "who is the Ulti-Man based on?", I don't have such a straight forward answer... when I got into MMA, the consensus among fans was that it was Bas Rutten, but there was always a small contingent of hardcore fans who claimed that it wasn't the case, according to Bas himself and other circumstancial evidences.
I honestly don't remember much outside of that... I don't think it was a specific real life dude, though.
If I look it up and find out more I'll post it here.
Cheers guyz o/