no, you'll get him in chase missions and survival trial for free

Ohh okay thanks bro

Even if you wouldn't eventually get him for free, he just doesn't do anything special enough that you'd miss him. Ninjas are cool and all, but the game forces you to invest other resources (like cultivation and awakening mats) to even use them effectively for most anything. But power is power. Redemption Merchant should be used mostly for power, in my opinion, and if you're getting ninja frags then it should probably be mostly people like Hinata and Kabuto that you can refine into Iruka frags that will also net you summoning/seal scrolls. Space-Time Shop has tactics option and thread - depending on where you're at, it should almost certainly just be used for one of those purchases, imo.

Also in the Ninja interface it is said that Choza can be obtained in the seal treasure. True or false, it is unknown

he is one of those nijas that are good one in a while like in sa and stuff like this,like most ninjas

Choza is an interesting character. He's somewhat niche in that you need a team that revolves around him for him to succeed. However, if you can figure out a nice creative team with him (I:e using Lightning main's leech to fuel his healing buffs) he can be fun to play and a neat addition to your team.

He is in seal treasure, I pulled him