I want a Checkmate series so badly and I hope it happens.
As for cameos…
I think maybe Jimmy Olsen shows up since we’ve heard he is getting a series that explores some of the weirder DC characters. If a bunch of creatures come through these inter dimensional portals, it could lead right into that.
I don’t think we will actually SEE Brainiac in Peacemaker (as much as I would WANT to, I’m going to temper my expectations). I do think they could hint at him though. I think that the QUC alien technology is what Brainiac uses to condense cities and possibly entire planets. So we may get some insight into that.
I think we’ll see Lex again in this episode, maybe out of prison now or in a Club Med type of prison setting. Maybe working on his suit.
Waller is definitely coming back so I think she shows up.
I heard rumors about Booster Gold but I’m not sure how he would really factor into any of this yet other than for it to just tease the next thing and Gunn doesn’t seem to want to do that.
I was hoping to see Superman but Gunn seemed to imply that he’s not showing up. And maybe that is a good thing given Peacemaker’s raunchy humor. A Superman appearance could lead to kids watching the show when they probably shouldn’t yet.
Maybe Mr Terrific shows up since we had the other Justice Gang folks already. He would make a lot of sense (and if Flag wasn’t an idiot, he would have called him up to help instead of enlisting Luthor). It wouldn’t be a surprise if Terrific has to come in a mop up ARGUS’s mess.