Mercury can take out Hazmat easily since she's not a living organism anymore (she doesn't eat/breathe/sleep) and she's composed of a pretty dense material.
Hellion and Striker can go either way but my money is on Hellion.
I see Mercury winning her fight vs Hazmat then helping out Rockslide while Hellion either holds off or outright beats Striker. Mercury would have to avoid Striker though since she has problems with electrical attacks. So as long as Mercury doesn't face off vs Striker, I give Team Young X-Men the majority wins.
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..even the outer hells are indifferent matters for they bow only to potent and archaic Nodens.