I don't think he'd get past the second round, honestly. 1st round he fights intelligently, staying on his bike, pinging Matthyse with jabs and quick Combos. 2nd round he gets cocky and sloppy, gets caught with a big shot and does his usual thing of wanting to hurt his opponent in return, stands, trades and gets KTFO.
With all due respect(and your second point is spot on) many of us knew even back then that Maidana wasn't all that. And that doesn't mean it wasn't a good win at the time. Just not quite as good as some thought.
2nd,khan may have a good first round because his speed,but the second round matthysse would figure him out and put him to bed.
I would go like the Garcia fight just Mattysse would finish him faster as Garcia isn't a savage finisher like Mattysse is. Make no mistake if Khan fights this guy it will end his career.
Knowing Khan somehow he'd manage to stay in there for atleast 6 rounds staying on the outside. Then the police would raid the ring and arrest Matthysse for attempted murder
Khan would be on his bicycle from start to finish as he normally does, but he would definitely get caught between punching exchanges.