Jedi don't have a lot of use in this game as a faction outside of unlocking Grand Master Yoda (another Jedi with limited usefulness from what I can gather), and the defense mods challenges.
With that said, Ezra is one of the best of them, and is incredibly useful. He has both Jedi and Rebel tags, and he's one of the few Phoenix characters who can be used outside of a complete Phoenix Squad. He's the main damage dealer for Phoenix and definitely the one you want to be geared/levelled up the most.
But I would still recommend pausing your Ezra farming at some point to unlock Hera. You'll have to have her to make Phoenix work since she's the only leader and the one that allows the rest to share their abilities. Once you get her to 5 stars, go back to Ezra and take him the rest of the way to 7 stars before finishing Hera. In doing this, Ezra isn't likely to be your first 7* character (if you're farming all of Phoenix together, you'll probably/hopefully finish Zeb first).