Optimize my Arena Squad

I'm working on getting a First Order squad already -- both FOO and FOTP are five star, so I've made some progress on them. Getting FOO up shouldn't be a problem, I have some currency stockpiled. FOTP is tougher as I'm trying to get Boba up to G10 first.

I have a bunch of 7* rebels -- Ackbar, Cassian, Leia, STHan, Wedge, and Biggs but they're all level 70 and G8.