Don't they train together? Miller said he'd love to fight Edgar again...
Jimmy is at AMA in Whippany, and Frank is at Ricardo's in Hamilton, but the schools train together from time-to-time including a regular Sunday session at AMA. I think I recall Jim saying that Frank hasn't been up much recently, but they have both spent a lot of time sparring and rolling together the past few years.
As for the fighting again, it's something he's said plenty of times in the past that it wouldn't be something to do if they were both in the middle of the division, with plenty of logical fights, but would have no problem with if they find themselves top dogs, which is something you could make the argument they'll be after Frank beats Maynard. He considers Frank a friend, roots for him all the time (somebody asked who he was pulling for in the Edgar-Maynard fight in one post fight interview. Seriously?) but, as Jim puts it, "we beat each other up for free all the time, why not get paid to do it?"