Well, I'm only gonna speak on the guest character that I'm personally hoping to see.
Pennywise - Sewer System stage. It could be like the area in the reboot where all the kids are floating. Then, I guess for a stage fatality they could float too.......hmm idk. It doesn't entirely fit unless it's Pennywise doing it. (Although that could be a dope normal fatality where his face stretches open like the movie. 10/10.)
Or or or or or or or....omg....when you win a match without doing a fatality or anything, one of his winning animations could be him making the opponent 'float' and then it cuts to the sewer stage and there could be a ton of easter eggs in there of characters. Similar to the Predator winning animation in MKX.
Guest characters can fuck off, to be quite honest. MKX DLC was incredibly disappointing solely because of the potential inclusion of so many great MK characters being disregarded in favour of four boring guests. Just imagining how much better the game would’ve been with the inclusion of characters such as Fujin, Sindel, Jade, Nightwolf, etc. is saddening.
Scream about guests all you want, but they're going to happen. That's just something I don't see why people even bother. Campaign for characters to get added, always, cause if they don't hear you now they usually always take it into consideration for the future. But, to even suggest no guest characters...
Cutting off guest characters just seems like the dumbest idea.
If they were to release a pack of 4 MK characters: Sindel, Fujin, Jade, Nightwolf
Then released a pack of 4 Guest Characters: Pennywise, Spawn, Ash, Pinhead
The Guest pack would outsell the MK pack tenfold.