As interesting of a fight this would be, it stops being interesting the moment you put omega mutants into the equation.
Let's just go over their powers:
Jean Grey - On her own she is the most powerful telepath who ever lived. She can more or less just make the inhumans kill themselves with a thought. She's also the most powerful telekinetic who ever lived, she could tear them all apart at the molecular level. But she's not just that, she's the avatar of the phoenix force, one of the most powerful cosmic forces in the universe which gives her pyrokinesis on top of her telekinesis and telepathy, and it also means any death she has will only be temporary as long as the phoenix force remains intact.
Scarlet Witch while not always at her top power level is arguably the second strongest mutant who ever lived. Her power is just weird, she can change reality to how she sees fit. With three words she depowered all but a hundred mutants on Earth and remade reality to fit that. She can change history, rip holes into other dimensions, and take everything you are away from you. The good news is her power is hard to control, and she rarely does control it at an omega level.
Franklin Richards: The most powerful mutant, and arguably the most powerful person to ever exist in the 616 universe. When the universe ends, Franklin is still going to be there. He can create pocket universes, and just do whatever he wants. He is Deus Ex Machina incarnate.
Hope Summers is Rogue on crack. Unlike rogue she does not need to touch you to copy your powers, just be in your presence. On top of that she can take your powers and beef them up to an omega level. She is also an avatar for the phoenix force, go figure. Hope didn't really get to live up to her potential in the comics, but when she was time traveling with Cable we were introduced to one of the most powerful mutants.
Iceman, or Bobby Drake may seem underwhelming at first, but his power gives him the ability to slow molecular movement to nil, lowering your temperature to absolute zero. This is more damaging than burning you alive or tearing you apart, it breaks the laws of physics. On top of that Iceman can create an army of ice golems to fight for him.
Storm is a potential omega-level mutant, her powers have rarely gone up to that level but she is capable. She can create storms that span continents and focus their destructive power on a single point. She can freeze armies, shatter them with gale force winds and tornadoes, and vaporize what's left with the strongest lightning storms to ever exist.
Onslaught is one of the strongest telepaths to ever exist, and has the twisted personalities of Xavier and Magneto to begin, and later is absorbed into Red Skull. Telepaths on their own are ridiculously powerful, but Onslaught was even able to subdue Jean Grey.
And what do the Inhumans have to counter? Blackbolt?
Sure Blackbolt is powerful, like Hulk-powerful. But he isn't a cosmic threat, nor is he an omega mutant. Being able to scream and rip people to shreds isn't going to save you from being torn apart at the molecular level, or your mind being hijacked, or stop you from never being born.
The Omegas are just beyond everything in the Marvel universe.