Looking for Squad Advice

I'd say the best splits you could make here would be something like:

Rey, Ben, then choose between CK, Barriss, JTR, 50-rt (Make sure Ben is weakest in this case) , Ezra or L3. I would personally recommend CK and Barriss and then a third.

The problem with using GK is that the crit immunity has anti synergy with both CK and Barriss, though he is still a decent tank for the team.

Jmk, CAT, Snips, Padme, and GK/windu (don't know if it really makes a difference which one)

Gl Ahsoka, Huyang, GS, PSW, and either Ezra or fulcrum.

Choosing where to put Ezra is up to you, as both Rey and Ahsoka are easy to counter without him. The difference between the two is that Ahsoka is generally a bit more expensive to counter than Rey without Ezra, but team comp and Datacrons can throw off a lot more Rey counters than Ahsoka counters. This is true both with and without Ezra.