Fox doesn't phase me. Snake isn't that rough until he gets in or dthrows you. If you can keep him out you have a better chance.Pika is my secondary. He does have the better MUs vs DDD, Falco, Snake (slightly), Wolf (lol), Fox, MK slightly ( I don't think MK:ROB is any worse than 6:4, MKika is 55:45 or almost even on some stages.)
The only one not named MK that is maybe a slightest hindrance to this team is Lucario, but it isn't too bad.
As for Lucario, I know the LucariovsROB MU really well. My dubz partner mains Lucario.
But DDD and Flaco...those are the toughest. I am pretty bad at the MK MU but that is mainly because I play the MU like 1-2 times a year so I really don't have much practice in it.