As someone that loves having all of the teams and using all of my toons just because, I admire your goal. I personally like TW Defense and think it is a good place to test teams. If your teams can win under AI control, its a pretty good team. Last TW 6 of my D teams had 39 wins in front and center zones. Ive done slightly better and worse but they usually perform pretty well on average because Ive spent time on them.
BUT don't spread yourself too thin. Depending on your GP level this project can break you.
But if it were me: Remove Jawas, Tuskens and Gar Saxon teams. They just are not useful right now and a waste of resources.
As far as specific counters, there is a good discord run by @SidiousIsPikachu that is very helpful for such things, even if I dont agree with him that you only need 14 good teams. ;)