You should check out the in-game journey guide to see the requirements for unlocking the various legendary characters. F.ex. 5 Phoenix characters unlock Thrawn, 5 Separatists unlock Padmé and so forth.
If you prefer continuing with a jedi team and taking GMY to 7* you should focus on farming Old Ben, Kanan, Ezra, Jolee and Bastilla Shan since they all are part of the requirements for some other of the early legendary characters. Stop wasting more resources on JC and Mace Windu. Bariss is mediocre. Don't gear Old Ben too much. With your guild you will soon unlock General Kenobi - a much better jedi/Republic tank.
