I've been running mostly a Jedi team for arena since I started and I'm up to 75 now...don't have access to all Jedi yet either.
What I've been running is QGJ lead, Ezra, Mace, Lumi, Barriss. I usually go 5-0 on my arena fights but the problem is with no tank you don't stand a chance on defense, and Lumi is garbage if they're focusing guys down one at a time so your blasting off her heal while 3-4 of your guys still have protection up and getting no benefit from it so Lumi is really only in my squad right now just due to lack of better options ready to use. I've been getting my Kanan leveled/geared and dabbling with him a bit...some fights when they debuff a lot and can't get rid of his taunt he's a rockstar, but other fights they just strip his taunt and he's slow with a 4 turn cooldown on it(til level 78 it gets -1) so he's pretty much a waste of space for a few turns after that.
I think Bennehftw called it though...Jedi really aren't all that good early on. I plan on still working my Kanan a bit and see if he gets any better(I'm hoping the cd reduction reduction at 78 and modding him with some crit damage mods since he crits a lot will make him a bit more useful)...but it really seems like Jedi get screwed in terms of tanks til you can get GK compared to the tanks you get in other factions. zQGJ and Yoda passing out foresight left and right seems like it can help with that a bit...but obviously you or I can't zeta yet because of our levels so we are limited there.
I think ultimately for pure Jedi I plan on running zQGJ lead, Ezra, GK, and then rotating in some combo of Barriss/Anakin/Yoda depending what I'm up against, possible Kanan depending how he turns out when I finish him, and long term I'm sure Jedi Luke will end up in there somewhere...but really I've just accepted that my Jedi squad isn't going to be a top 10 team anytime soon.