By George folks--I'VE GOT IT!!! I know two possible means of how AXIS can be resolved AND things can go back to normal without a hitch!
Option 1: We call in SGT. PEPPER'S LONELY HEARTS CLUB BAND and have them sing.
"All You Need is Love" managed to drive the Blue Meanies out of Pepperland, so why not do the same to cancel out the inversion effect? And with the inverted X-Men now sporting three blue meanies of their own (one of whom with a big A on his belt), who WOULDN'T want the singing saviors of Pepperland to intervene?
OR, option 2: Optimus Prime is called in and he unleashes the full power and combined wisdom contained in the Matrix of Leadership.
When he did this, he saved the entire universe from an eons-old hate plague. As one of the ancient Primes told him as he ventured into the Matrix, "The only way to fight such madness, is with wisdom." And indeed, with inverted madness fallen upon the Marvel U's heroes and villains, Prime unleashing the power of the Matrix may be the only other way to light their darkest hour.
(.......OR there's always the last resort--plucking Bob Marley from the timestream, teaming him with Cheech and Chong, and getting everyone assembled on Genosha high.........)