I don't think it's the case, since the only difference between mist and fog is that it's called fog when you have a short range visibility. So if you cannot drive because there is "neblina", it's definitely a fog.

Just my 2 cents.

Yeah, kind of...the meanings are definitely close enough. Just that, 'neblina' is definitely a noun, whereas, 'misty' is more of an adjective.

Depends on how strict/literal they want to be.