In regards to Magneto solo'ing Juggernaut: I know its been a while since Jean tried tk to levitate and BFR Juggernaut but is there any reason to believe that Juggernaut couldn't walk against Magneto's magnetic force.
But yeah, he loses to the team.
I'd honestly assume the spell would protect him vs anti-matter as against nearly any other attack type and he'd shrug it off.