@vanillacupcakes: I had not seen that one. You are correct that it is pretty much the closest to fanservice with him. I also know from personal experience that it's easier to get biceps than abs. But Nathan would be able to get a trainer to help him achieve it better than an average joe like me. He looks like he's got a pretty decent core from the vid though. I don't imagine he's any worse than Griffin was.
The only reason I could say Freddie would lose a fight is because of lack of fighting experience. We've never seen that he has any actual fighting ability, and it is hard to believe that his mother would let him take self-defense classes.
I've never met a girl like Sam, but women do tend to be pretty scrappy fighters. And they are able to build a lot of strength without bulky muscles since they don't have all that testosterone. On the other hand, Jennette is obviously pretty strong to be carrying guys on her shoulder like that; and she would probably have done several takes. If she were doing a fireman's carry, I could see it being easier for her with the weight distributed; but she always carries them over one shoulder. I'm 5'8" with a solid frame, and I might be able to do 250 lbs like that if I balance them right.