It's pretty obvious they don't have bad breath.
You've been a chronic halitosis sufferer for a while now, noptical. I think you should be well known with other people's reactions to a chronic halitosis sufferer's breath.
(And someone please save the story about how they are actors. Even actors have a nose and will most likely refuse to kiss someone who suffers from halitosis).
It doesn't surprise me though, pretty much everyone I know doesn't have to worry about their breath. So if you just pick a random person you see on the street. The chances are much bigger he doesn't suffer from halitosis.
The coating they have is just from food I think, I mean a lot of people have a coating. Especially those who never brush their tongue, it may even have a brown colour. But this doesn't mean they suffer from halitosis.
Now that you mention this succ, one time at school during gym class a boy from my class was sticking his tongue out to another boy. The other boy's reactions was "Aah look it all white shit on his tongue". He was really grossed out by it. I've talked to the boy who stuck is his tongue out many times, I can assure you he is not a chrnoic halitosis sufferer. But wtf who cares, I'm not even sure why I'm typing all this stuff, maybe I'm just trying to say that having a coating doesn't mean someone suffers from halitosis, which you probably already know.