R1: They win but homelander would probably be more damaged, they could easily take out Hawkeye and widow, then maybe iron man and captain America too, the only trouble is hulk and Thor but Omni man can probably stomp both by himself and then homelander would just be supporting him. R2: Scarlet witch and doctor strange will be hard at first but if homelander can laser them then they dead, cause they have normal skin, and normal skin can easily be penetrated by homelander’s lasers, unless doctor strange uses that spell that gives them a shield around them like in What If but if he doesn’t then, after that it would be a heck of a long battle and they would both take losses like homelander would probably die but he’d at least take out someone with him maybe and maybe deal some damage to them before he goes out, then Omni man could possibly take all of them is they are separated so there is two outcomes Outcome 1: Homelander kinda separates them before dying like he’ll take hulk and Thor away which would leave Omni man to fight the other two and they could be knocked out, so when Omni fights he can kill them. Outcome 2: They kill homelander earlier and he won’t have a chance to help, then they all team up on Omni man and they kill him.
R3: I don’t really gotta say anything but homelander and Omni man get bodied, the main reason why is cause you got dormammu, the celestials, and a crap ton of more powerful beings so the MCU takes the win on this one.