Foxer said it well, to be STR ready you need to have strong squads for the raid ready or be very close to have them ready.
You have jtr team at G11+ which is great, could use zeta on bb8 and try to push them all to G12 and you have probably the best team right now ready. That is big + for you if you want to get into guild that is attempting heroic STR.
Your problem right now is that you use your jtr in p1 and have really nothing for other phases, but you are not that far away from "being ready".
There is quite a few teams that work well in p2. Bit more work on imperial troopers, since you already have Veers zeta should work well. Also if you gear up phoenix bit more, especialy sabine, they can do decently as well or you can work on leia team. Choose which team you wanna focus on. A lot of people need to use more than one team to get 2% in that phase if your guild dont have enough JTR to get through p1 and p2.
For p3, chex mix is currently considered best and you have all characters close to being ready. You need to take raid han to G12 and get his zeta, and boost a little bit other toons.
A lot of guild wants nightsisters for p4. You have all the old ones at 7 stars, but you need both zetas on asajj and gear them up quite a bit.I dont know right now what NS is the best.
There is plenty of guides on what squads use for each phase, how to mod them and much more, just do the research, go through your roster and choose what you want to focus on.