Vulcan, Rachel, and Iceman can possibly be dealt with fairly quickly (well, at least Vulcan and Iceman, depending on whether Rachel is allowed PF access). Nate and Cable (essentially Nate again) are a bit redundant (literally), and Surfer alone should be able to counter them long enough for another Herald (Stardust, likely) to even the odds.
Given this roster of mutants, I see the Heralds winning. Replace Cable with, say, Proteus, or some other powerful mutant that doesn't have the exact same power set as Nate (and Rachel) and this equation likely changes drastically.
comes down to who's fighting who and the teamwork. IMO Vulcan if he doesn't get taken out herpidy derpity could be a big problem with his energy drain against a lot of team 2 and team definitely could protect him long enough to be a factor. Iceman really doesn't do much here and I don't count anyone whose had a recent win over thor at the moment... as it appears Thor was replaced by an average asgardian... or a skrull/dickery with how he's been getting jobbed.
Rachel (sans PF) knocked Thor around after he attacked her from behind. She also stalemated capt america and beat Iron Fist and black widow. quicksilver and in her fight with IF she beat him and even knocked back panther as he was also trying to sneak attack her in her fight with IF.
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As powerful as Iceman/Rachel could be, they are not exactly on the same terms with heralds yet. And as good of an energy manipulator as Vulcan is, even if he can out manipulate any of the heralds (doubtful for some of them), any single one of them can realise this and take him in h2h- in war of kings when he was out manipulating Warlock, the minute Adam started punching/throwing stuff at him he was on the defence, and every single one of these heralds are deadlier than that version of Warlock up close.
And although Cable/Nate are powerful, any of the top tier heralds (Surfer, Morg, Stardust) can stalemate either of them (and tbh, Surfer at least could beat either imo) until the heralds have a numbers advantage, as it shouldn't take too long to take out Iceman/Rachel.