if absorbing man can absorb the properties of thor, who is asgardian, i'm sure he wouldn't have any trouble doing it to a mutant, when he absorbs from people they aren't affected by it, only he is, so any resistance to magical attacks doesn't really come into it........ except that absorbing man would gain the same ability
Colossus has a chance. I remember when Thor outsmarted the Absorbing Man by making a cardboard duplicate of Mjolnir and Absorbing Man took on the properties of cardboard and got his ass kicked, and I've seen him take on the properties of water like an idiot and could barely hold himself together.
If Colossus could get in close or engage in a grapple and revert to his human form as AM tries to absorb him, he'd make AM have the properties of a normal human, flesh and bone, and then he would just have to disengage, change to armored form and punch him out.
In a grapple, Absorbing Man would always be in physical contact with Colossus so even if Creel turned to human as Piotr, he's still stronger than him, so he'd break the mutant's neck the moment that happened. Plus, Absorbing Man starts out in steel form (due to a piece of metal he always carries around), so that scenario wouldn't really play out.