Why are they french ?: (because if i have to write dialogue for Pluey I'd need it to be in a language i actually speak...) Their names are slightly differently spelled french words so it felt right to make them french. Plus, with Pluey not speaking english, it aligns with my headcanon that the saxophone noises the shadowguys make is an actual language that can be understood...however no one at the studio speaks french aside from Jongler and Battat so Pluey doesn't usually talk much

Lore wise, I would say that Jongler is from a french family but grew up in Texas before moving from their home to work for Tenna. Battat grew up in France with one side of his family being american and moved to America after having finished university to eventually work for Tenna

As to why the hell Pluey is here despite not speaking english, I imagine he would be those sad french people idealizing the american cinema industry so one day he just impulsively packed his things and moved there, ending up in Tenna's studio but sadly not as an actor. He still has this dream though

Why the mask/scarf for Jongler ?: They are terribly embarrassed of their tooth gap so even when they takes off their mask they try to not open their mouth too much, often making it hard for others to understand them