It looks like we'll be focusing on Jet's past quite a bit in the live-action Cowboy Bebop series from Netflix as the latest round of casting additions point to the series tackling a few episodes from the original anime series that dove into why Jet left the ISSP (Inter Solar-System Police).
First, Geoff Stults (Stargirl) has been cast as Chalmers, Jet’s ex-partner. Fans of the anime series will remember that Jet's ex-partner in the anime series is actually named Fad (pictured above) and he double-crossed Jet when he back a double-agent for the European syndicate. Fad ends up shooting Jet and it's that wound which leads to Jet losing his arm and having it replaced with a robotic one. These events were covered in the 16th episode of the anime, titled Black Dog Serenade.
Next, Law & Order: SVU veteran Tamara Tunie has been cast as Ana, a Martian bar owner. Tunie is likely playing a version of Anastasia, an affiliate member of the Red Dragon crime syndicate and close friend of Mao Yenrai, Spike and Vicious' mentor. While unconfirmed, instead of Ana being a convenience store owner like her anime counter-part, the character will be a bar owner and might actually be the owner of the Rester House, as evidenced by the next character.
Mason Alexander Park has been cast as Gren, a memorable character from the series who stars in the two-part episode, Jupiter Jazz (episode 12 & 13). Gren is an ex-soldier in the Titan War and served alongside Vicious. Without going too heavy into spoiler territory, he also crossed paths with Julia later in the series and has a memorable shower scene with Faye. Netflix appears to be crafting a more succinct story as Anastasia and Gren were not connected in the original series but in the character description, Gren is described as Ana's right-hand person.
Rachel House, who previously played Topaz in Thor: Ragnarok, has been cast as a gender-bent version of Mao. Through flashbacks, it's revealed that Mao is Spike and Vicious' mentor and superior in the Red Dragons. The character appears in episode 5 of the anime series, Ballad of Fallen Angels, where he's betrayed and usurped by Vicious.
Lastly, that brings us to the two characters Shin and Lin, who were brothers in the anime series. The Netflix show describes them as twins, with one of the characters being a girl. Ann Truong will portray a gender-bent version of Shin (pictured below) while Hoa Xuande plays Lin (pictured above). Lin plays a key role in Jupiter Jazz, protecting Vicious from both Spike and Gren while Shin has a lead role in the series' two-part finale, Real Folk Blues. It seemed that Shin, the younger brother betrays Vicious following the death of Lin in Jupiter Jazz, alerting both Spike and Julia that they were in danger from the Red Dragon elders who were out to destroy Vicious and anyone connected to him. Shin reveals that he was always hoping that Spike would return and stop Vicious, taking over the Syndicate himself.