Re: Alexander Marcus/John Paxton connection?
I think Marcus could be said to be xenophobic to some degree, seeing as how he evidently strongly dislikes major alien powers, notably the Klingons, and seeks to destroy/subjugate them, making the Federation more totalitarian.
While there was indeed a certain amount of speculation about a possible Paxton connection from the time Weller's casting was announced, I don't think such a link is really necessary in order for Marcus to exhibit any or all of the qualities you list.
"It is my belief that nearly any invented quotation, played with
confidence, stands a good chance to deceive." — Mark Twain