cls' IBAT is one of the best zetas in game. making rancor easy, and making it possible to solo the haat after few things. its far from you, but you will zeta it eventually. however, the rest of the zetas not sure you wanna get. Ezra is totally luxury zeta. not something for 5th zeta, but more of something like " i hoarded 5 full zetas that i can throw, lets waste one". Finn is useful but eventually you'll stop use it altogether, because you'll have better options... AV is a great zeta, for Raids especially.. HSR and HAAT. but if you are far from HSR, and you might farm Yolo (which is very easy farm), i dont see any reason why you should zeta AV now. Old ben zeta is a defensive, tanky zeta. i consider it luxury. it give 0 usefulness in raids, and very low in arena, especially in the current meta (the trio alone have 3 dispels) and even in your team (that i guess, have ezra and bast there) have already 2 dispels. add thrawn the meta survivor to this, and you have lot of dispels which make this zeta pretty useless. totally luxury imo.
so, i guess there are no other answer besides CLS ibat. at least not in my opinion.
and since the guys who think that ezra's zeta will be useful because its in arena team - there are other ways to improve your arena team. cheaper ways. whether farming characters that you will use a lot (like GK, or hoda, or some new team) or farming new great mods that will stay with you forever... ezra zeta will eventually sit out because its not crazily useful zeta.
personally, i use thrawn cap ship, and i use thrawn in arena for over a year, and i still dont have any of his zetas, even tho i always have enough zetas. right now i have 5 full zetas ready to be dropped... point is : having someone in your arena team does not mean you should zeta him right away. there are reasons why to zeta or not zeta someone, and you need to think long-term. putting zeta on someone simply because he's in arena team is bad thinking and meta shifts will kill you eventually.
