Hey PabloZed I really like this thread, thanks for posting. I'd also like to point out something here.
The title of the thread, "are the UFC's practices anti-competitive?" asks a somewhat different question from what the other poster named john (who seems to know antitrust law at least somewhat well) is answering. He's assessing whether the Alvarez dealings violate the antitrust laws. You seem to sort of be thinking about the UFC's motives underlying the Alvarez deal. Both are interesting considerations; if the other john is to be believed, though, this deal probably doesn't amount to a violation. If, as he says, the antitrust authorities would have to "prove that the signing of Eddie Alvarez had nothing to do with his in cage talent," that's obviously very hard to do. Clearly, the signing has at least SOMETHING to do with Alvarez' talent.