For Quinn gonna go with:
Gameplay - CertainlyT because he's probably the most capable person when dealing with out there champions like Quinn & Valor. I think he'd be the best person for the job and would be able to introduce mechanics that actually make the two feel like a tag team rather than the dumb taxi theme we have going on right now.
Story - CoolRadius, Narrative behind Gnar, WAAAARGHbobo, Narrative behind new Pantheon.
Atm Quinn is just a bird girl who fights for Demacia has a bit of spunk. These narrators have worked on Kled, Gnar, Kayn, and Pantheon. All characters who can be simple on the surface but have a ton of depth once you go peel back a few layers. Old Quinn had that kinda depth imo because of her brother Caleb but that is gone now. Aside from a potential lore event, there's nothing that really makes her unique imo (I quit playing Quinn entirely now because of gameplay AND lore). These writers can give Quinn something cool and give her and Valor some much-needed characterization.
Visual - Art teams behind Rakan, Kayn, Taliyah. A Hing Chui who worked on Kayn and Camille.
Honestly, I'm pretty cool with Quinn's visuals atm. Her face could be nicer and I honestly don't wanna see her become a new T H I C C grill like Irelia, Kai'Sa, Camille, Kindred, Evelynn w/e. Her love her current armor design because it looks lightweight and cool while also having some protective metal bits and stuff. I actually fear that if she got a VGU she might lose some of the intricate details she has going for her. I think it'd be cool if the animation techniques that Riot used when making Kayn were also used for Valor.
Edit - Realized I kinda didn't do it properly...
Gameplay - CertainlyT
Narrative - CoolRadius, WAAAARGHbobo
Visual - Hdot