Okay then...
Sure...
No.
Depends on Gorgon/Fiery Fang thing. One FF variant leaves him to bleed to death, gorgons have... different solutions to it.
Misunderstood unless I made a fuck up somewhere if they betray the MC, Susan's line in the aftermath is: SU "The bitch and her brother abandoned us." And Susan doesn't die because she isn't in any danger, mostly she faces humans, and the demon while is loyal, to a point, to Tamara isn't a puppet, she makes her own judgments.
Ehhh... Technically there is just one epilogue that varies with the choices you made. But there are a lot of variations obviously, if something isn't mentioned it just means you either chose "poorly" and the MC doesn't have any idea what happened to them. And still probably forgot some stuff... But if you mean ending screens, there are 6 in total.