For a high level Jedi team, you want Qui-Gon as leader with his leader ability zeta'd. If you can't get a zeta on him, Ima-Gun Di and Jedi Knight Anakin are the best other arena leaders. Qui-Gon zeta is huge though, it turns Jedi from meh in arena to top 100 capable in old shards (although that's only really if you have GK). Obviously, it will also depend on the age of your arena shard.
Grandmaster Yoda and Jedi Knight Anakin are great with Qui-Gon, then Old Ben and Aayla Secura/Ahsoka Tano are probably the best to fill the other two slots.