#at the same time cody had also jangos voice in ep iii

Anyone familiar with the Republic Commando game knows how Delta Squad’s voices are unique. The Prime Guide states that “despite being trained by Walon Vau, Three-Eight somehow inherited Jango’s strong Concord Dawn accent and speech patterns”.

In Triple Zero book, when Omega and Delta Squads officially met for the first time during rescue operation, Fi noted that Boss and Atin sound very alike, only except Boss had stronger accent:

The whole squad maneuvered so they could see what he was looking at. 

“About time,” Niner said. Fi listened in. “Delta, Niner here. You been sightseeing?" 

"Boss receiving. Sorry, we had to stop and ask for directions.” He had a voice very like Atin’s but with a stronger accent.

So it is fair to assume Atin sounded like Jango Fett as well as Boss.