You can do GW with 4 droids and JE. But it will limit you with some builds. You will need a stun either Daka that could help you on dark side missions, or RG for certain builds. Also Poogle, Phasma, and QGJ are very multipurpose useful characters
You also might consider getting Yoda for raids. For that you will need 5 yedi. There are multiple post on which yedi to level up.
You can also experiment with 88 lead once you omega his leader ability.
As far as only leveling Teebo he's only part of what you need for Raids. There are two main train of thoughts for raids either TM manipulation or DPS.
Right now you are spreading your resources to thin. If you are comfortable with your arena team. Then focus on speciality modifications for GW. If your main focus are raids then you might want to focus on those characters.
Ps: I don't have Rey and I score first in my guild for T5/T6
