I say both Colossus and Thing solo. I like rhino but Colossus and Thing are better fighters, similar if not superior in strength, and arguably more durable (im pretty sure spidey has KO'd rhino with a shot to the face, that wouldnt happen to Colossus or Thing). Rhinos horn shouldnt be able to pierce Ben or Colossus's skin either. The only thing rhino has going for him here is his running speed but Colossus and Thing should both be able to evade a straight on charge long enough to Ko the big fella.
Rhino really has no chance, since his strategy is to overpower, and they both are about as strong as he is, and they are much better fighters and more durable. Especially Ben he's used to hold his own against much stronger fighters like Hulk or Ronan The Acuser. He's all heart, i don't think Ben knows hot to quit, he just soldiers on.