Best JMK squad?

So I made the uneducated decision a year or 2 ago, that I would go after jmk as my first gl as a f2p with 2m gp. I now have 3m gp and almost all of the requirements done. Unfortunately only being at 3m means I haven't unlocked proving grounds, so I don't have CAT. Is there a character that I can swap for her while I work on obtaining her? If so what's the best complete squad for jmk.