Firesweep or Brave Bow on Cordy?

Depends on what you want her to do and IV.
Go with brave bow if you want pure offense but +spd is better with a brave bow so she can quad but +atk if you just want pure all in dmg

Go with Firesweep if you want "chip damage" but can still kill pretty easily and +spd is better so she can double.

IMO go with Brave bow.

If you have a spare Faye or don't use her, Firesweep. Cordy runs it well, while almost any bow can run a Brave Bow. I feel Firesweep just suits her statline much better.

I also built a Klein with an identical build for reasons...