Returning player - help with new goals

Rex lead is still widely used as a (soft) counter all the EP lead teams out there. However,your team composition is a bit outdated. Nihilus, EP and MT (yes, even at 3*—4*) all work quite well.

Alternatively, you could switch to an EP lead yourself (zetaed preferably). With EP, Vader, TFP and Tarkin you have a base for a good team, which can bring you to top—50 potentialy. A good 5th would be Thrawn. To unlock him you will need a team of 5 Phoenix charactets at minimum 5* but preferably all at 7*.

If you want to unlock Thrawn's capital ship, the Chimaera, you should begin farming/developing your rebel ships, including ghost/phantom. Yes, you probably have a lot of ships to farm, so you are going to have to make some planning here. Otherwise, Tarkin's Executrix seems to have gotten a slight buff with the recent changes to ships, and looks quite promising.

Good luck :—)