I don't know why the car has the persons name, but it's the same thing with most peoples smartphones. People usually never turn off bluetooth when not in use and it's always blasting their name. Though it is of course easier to see who Oscar is when there's a whole car model to match it to.
For car's, I wonder why they can't only blast a device name while in pairing mode. Dunno of it's just not a possibility, but that seems smort.
They don't need to, just give them a url, username and password and let them type each for each field.
(If you mean because you want them to configure a vpn to access your jellyfin instance, then just expose it to the internet and skip that, which surely you pretty much have to do for your plex instance)
Do people really think this or will they think (like everyone i know) that it's free and I can watch what I want.