I think Rogue "could" win. Unless there's some adamantium around. I'm not sure that Rogue could absorb Absorbing Man while he is in another state. (She can't absorb Colossus when he is in steel form) If she can, than Absorbing Man goes down. If she can't than most likely Rogue goes down. Absorbing Man has a better chance
That would be interesting. But absorbing man has fought the likes of thor and hulk and gave them a good beating. I know in the beginning they used to beat absorbing man by tricking him to absorb the properties of things like a paper cup. i think he has gotten smarter and developed a skill that wont allow him to absorb simple things