My first thought would be Cygnar would easily meet the Criteria of X-men. I mean look at my color scheme. They, unlike some of the other Warmachine factions, can easily switch up their support and still be well off. they do not necessarily having a staple model/unit (Granted eHaley but then again Prof. X. is always there somewhere
) Also, they are not "Super Heroes" per se just mutants, humans slightly better than the rest.
On the other note, Merc = batman reference is good. If I had to think of something I would say Minions = Clayface. Early on they give a beating and can improvise numerous tools but in the end they just aren't enough and he ends up geting washed away to comeback another day.