The Shi'ar rules an entire galaxy while Viltrum only rules a portion of one so the Shi'ar have far greater numbers. That said I don't know if they can overcome Viltrumites consistently in space battles. Marvel is weird when it comes to space armadas.
Vulcan recently stated he could crack the moon in half, for what it's worth.
Using Shibuya Megumi (until he gets feats in the current arc), Choso has superior CQC and stats. I don't think Megumi could block his ranged attacks very well given they pierced Yuji's defenses. He has Shikigami, but they mostly supplement CQC where he doesn't have an advantage.
Megumi has domain but it's not enough of a card for a majority I'd say. So Choso or stalemate through Mahoraga.
5-8 mostly comes down to your imagination. They have the strength scaling to put him down it's just that their strength feats are all potency based so you never really see them causing huge DC or turning opponents to mist. They have the strength, they're just never written that way. Choso could try poisoning or restraining him. If Todo lands Black Flash that should work.
@sy8000: The wording seems clear to me, if you used a cluster explosive on a Special Grade, it might work, that's it. Nothing in that scan remotely implies this in between step of that energy having to be concentrated in a weapon or whatever.
I cited the exact wording. The context is he's talking about how much power is needed to beat them. No one is using an actual carpet bomb.
Examples 1-4 are physical and the one for special isn't. It's clear they aren't worrying about different attack types here. This just seems like really overcomplicating something straightfoward.