Whoops. I forgot to put the preferred squad.
With these changes, 2ndSister is much worse than she was previously. Her hero ability will stack thermals on her and 7S ridiculously quickly even if she uses her basic or non-damaging special. There is no good reason to use 2ndSister right now.
As a result, my recommendation is that 8thB should always be your supplementary attacker to go with your core toons of GI, 5B, 7S, 9S.
If you already have 2S at r7 and you don't have the resources to take 8B to r7 before the mission, you can still attempt with 2S, but I wouldn't want to try it.