Confused

I am trying to build a good team but don't know who to use. I want to use Luffy 3rd gear and Zoro because he's my fav character but things are not working out well i guess. Listed below will be my main team followed by the units I own.
Lvl:31
Team: (Leader): Jewelry Bonney
4* Shanks
4* Usopp Golden Pound
3* Chopper

Other units:
4* Gum-Gum balloon Luffy
3* Gum-Gum Pistol Luffy
3* Arlong
5* Ashura Zoro
4* Killer
3* Sanji
5* Sogeking
4* Vivi
4* Marco
4* Miss all sunday
3* Nami

bonny is not the best option in my opinion 
i would build a crew with a killer lead at first 
until ballon luffy is evolved to g3 
or i would evolve arlong and build a slasher crew 
with shanks zoro killer usopp


but evolving ballon luffy would be the first thing to do

Thank you but isnt killer a double edged sword cuz of his 1 hp effect....i was thinking of using him with marco so that i could keep up the hp.

you mean his special thats true but you would use his special to lower your enemys hp
so that you kill him within the turn but i dont belive that you can use his special because of the
35 turn cooldown except for a zombie crew.

as a captain he is decent cause you can use any type of unit just like
g3 and you dont need to hits perfect but because of that his damage output is not that high compared to g3.
he can clear all storymode and fortnights isles(if condition allows) 
so he is the best for now till you get g3