Going out on a limb here (and I'm quite ready for someone to come along and saw it off!), but I'm beginning to detect a gender-specific division over the big question of 'Should Wayne get an invite?' [For the record, I'll state my view very simply - No. He's not a friend of Ennis; Ennis has final say of who should come, so why would he invite Wayne?]
I notice though, that most of the people here who say 'invite Wayne' are women and those who say 'don't invite him' are men, insofar as it is possible to tell at all. Is this because women are more compassionate, forgiving and Edna-like in their treatment of people with dysfunctional qualities, wheras men generally are more hard-nosed, dogmatic and Ennis-like, basically saying 'I don't like you, you sumbitch, keep well away from me.' ? Given that its going to be a very-male-dominant party, and that most or all who will be there dislike Wayne as much as Ennis does, I think the men's opinion would be the one that matters most.