Jabari is not a fashion designer actually. Don't get me wrong he loves fashion but after the events of Team Flare and how Diantha didn't bother to leave her movie set to help out Jabari puts most of his time while Kalos champion into actually being the champion (i.e. patrolling the region and trying to keep threats at bay). After he's dethroned he works closely with environmentalists and fashion designers to make more durable, eco-friendly gear for trainers and athletes.

If Jabari had not become champion (and he would've decided not to take on the league had Diantha and the other Elite 4 had actually done their jobs, he pretty much only took on the league to figure out what was up) He definitely would have pursuing fashion design as a career using Serena, his boyfriend Grant and his cousin Cami as models mainly focusing on active wear but also doing high fashion as well

Oooh this is a good question

I'll start with Jabari. He's probably the biggest TV buff of them. When he was little he used to love Thomas the Tank Engine and Danny Phantom when he was younger (and he still watches them now honestly). In the present, he would most definitely be a The Owl House, Kipo and The Age of Wonderbeasts, Grey's Anatomy and Insecure Fan.

For Cami she's a big fan of books (if she wasn't so deadset on going into medicine she'd of been a librarian) Cami is a huge fan of The StormLight Archive, Animorphs, Hunger Games, etc. But she's also a bit of an anime fan so you could catch her watching Durarara!!, Ouran High School Host Club, Cells at Work, and Prince of Tennis

Marsha is definitely the Disney Movie lover of the group. She loves going to the Team Skull hangout and watching Encanto, Moana, Tangled, The Princess and The Frog, etc with the former grunts! When not watching Disney movies they're probably watching something like Hell's Kitchen or Alola's got Talent

Calla is the gamer of the group. She loves Ace Attorney, Splatoon, Animal Crossing, Undertale and Five Nights At Freddy. When she becomes champion of the Galar league she makes it a point to have regular game nights with the leaders and Hop so she can beat them all at Mario Kart (or so she'd think, Hop usually wins these)

Valen is definitely the documentary type of dude-er robot. He's really trying to understand human nature so he thought if he watched documentaries it would help. He may have found some conspiracy theory documentaries and became a Flat Earther for like a week. He also really like Precure

Jack is the theater/literature snob. He loves Broadway and any of classic literature canon