Great view, I forgot the say Rheagar and Arthur are my favorite characters. I love how Jamie talks about Dayne and George saying he was the best. I always wonder if Ned was looking for them think "holy crap where is Dayne" I personally think Dayne would have taken him out. Barristin was on par or close to Dayne and he said if he saw Robert smile at the body of Rheagar's children no army could have protected him.
As for question#2
We don't know for sure if Aemon faced Stark in a real fight or sparring, but his option means a lot. It makes it seem that those 3 were never beaten in single combat. I think those 3 working together would have been damn near unstoppable.
But I think Barristin, Cregan Stark and Jamie would be an amazing fight Jammie and Barristin know Daynes fighting style, Aemon would fight stark, It all depends on who fights Demon. I think he could kill Jammie, then help Aemon. Dayne and Barristin would slug it out equall till who ever was left came in to help.