Yes, definitely. This is because these phrases have completely different meanings. 'Never mind' is a polite phrase meaning 'Don't worry about it'. 'Never you mind' is a fairly rude comment meaning 'It's none of your business'. Don't confuse them!

In the US, particularly the South, you will hear "never you mind". The meanings of the two phrases are as explained by SuKi.

Depends on the context. Never mind is generally ok as long as the tone of voice is also ok. Never you mind is rarely used. I have only use it if joking with a friend and have never heard it used in a hurtful way but then again I could count on one hand the times I've actually used or heard it used.

Near you mind is more of a southern U.S. usage as someone else stated.

I agree with the second answer. As far as USA English goes, I've never heard anyone say "never you mind." Usually I'll say "mind your own" or "mind your own business." It can be used aggressively but I usually say it playfully to friends.