@TVF
This is all explained at The Apple, but the short answer relating to the Accuracy Arrow is that 5B counterattacks. When you counter-attack, you don't get to pick your target.
Meanwhile, Jawa has both an AoE **and** evasion in his unique (for a total 32% dodge chance).
So a very common problem in the opening is Jawa AoEs and 5B counters ... and misses.
Why is this a problem?
Well, because of Grand Inquisitor's unique
"Compassion Leaves a Trail" which states that if any enemy dodges an Inquisitorious ally's attack, all OTHER enemies take damage.
That means that whenever you attack Jawa (and 5B can't avoid this) you have a serious chance of taking 2 thermals per other Jawa enemy (per Scav's unique).
As for 7S, yes, we're worried about her assists, but this turn order and strategy still gives you the best chance to gain TenacityUP at the earliest possible moment in the battle. Without the TenUP everyone dies. With it, everyone is fine. But it requires 6 stacks of Purge before GI's turn. Someone has to go first and take the hit for the team. That someone is 7S who can convert buffs to Purge. If she takes someone to 6 stacks right away, GI TM Jumps and automatically goes next and no one else takes thermals. If not, another Inq takes a turn, 7S assists, and again if we reach 6 Purge GI will TM jump and grant TenUP.
Etcetera. The longer this goes on, the more 7S assists, but we can't get enough Tenacity on her to stop the Thermals and we can't force her to be dazed. So we live with the risk.
There is much more at The Apple if you're interested.