Who comes next?

I just finished Tie Fighter Pilot, who should I farm next between Chirpa, Finn, AAyla, or Jaw/Datcha?
Here is my collection, https://swgoh.gg/u/silvermajra/collection/
Any help is appreciated.

PS: Bonus Question!
Should I only gear one character until Gear 11 or should i diversify at a certain point? Mainlynlooking for heroic tank raid squads.