[X] (Missy) Overrun
It's simple, but describes both her ability to run fast and summoning tactics. Dispatch is a good second choice though.
It's also a Pathfinder maneuver for moving past an enemy
And not something you'd think of as a little girl being able to 'run over' someone on foot.
[X] (Laura) Scathach
Not the clearest choice, but so far the best of the lot since it at least ties back to her device
Fragarach
As much as I want a variant on
Milady de Winter to tie in with Kayleigh taking the name Musketeer, Milady de Winter is a villain in the novel and most movie adaptations.
Sadly most named Winter / White Queens are Evil, so finding a good one to reference is hard.
[X] (Kayleigh) Musketeer
-[X] (Kayleigh) Magical Musketeer Shining Shot in her head
Sadly my brain fails to come up with a good pun along the lines of
The Lone Gunmen and Calamity is already taken so we can't go with a variant on Calamity Jane.
[X] (Device) Starlight Trigger
Remember, her device isn't actually a GUN, so Starlight Blaster is a bit of a misnomer.
[X] (Team) Night Sisters
I'd argue that's just the right amount of Edge for a bunch of teen girls with magic powers about to put the boot to the Fallen. When / If they get male members or they grow older they may change it up to Arcana, but I think they can afford to be a bit edgy when their lead member is Calamity Witch.
Grue
Cricket
It doesn't have to be a perfect match to their powerset. In fact, I'd says it's better NOT to have your power describe exactly what you can do.
I'll point out that Grue's name is literally old English for "Darkness" so... exactly what his power does.
Cricket's power is the Echolocation effect, which ties back to a cricket's chirping. Granted it's a tangential relation, but a Thinker could figure out the connection in seconds of seeing her fight.