Can I be prosecuted by the arresting officer if I was not arrested on the scene and the business owners want the charges gone?

Yes you can and know way to know if the case will have the evidence required for you to be convicted. best to ask your Criminal Defense Attorney...

What is the process after you complete your full probation term?

None of us lawyers work for the probation department so your answer will come from calling them and asking.

Arizona methamphetamine laws

Google the penal drug laws. No clue if he will spend anytime in prison if he's not guilty.

There is probably an arrest warrant for failure to appear don't know call the Court and ask. There is no such thing as a statute of limitation for...

Can my son admit himself into a treatment facility while having a warrant for probation violation and traffic warrant

Sure he can, why couldn't he/ perhaps while he is in treatment you can hire a Criminal Defense Attorney on his cases to get the best result.

What is the time limit to answer to a complaint for revocation for probation? And what are the possible out come ultimately?

All of what you stated is a possibility. Since none of us lawyers on this web site have your case you will not get a specific answer only guesses.

What can I expect from a review hearing

The Judge to review the probation, compliance and violations.

Confused ,I had a probation violation for 2 weeks tried turning myself in twice

No clue as none of us lawyers have your case. perhaps your lawyer can explain.

Do I have to show up in court to expunge my record? Could I mail them a letter? or Could they call me? instead.

You will need to consult with a lawyer in Springdale, Ar and may not have to appear in Court if they can handle it.

How do I find out if my brother can get an aggravated robbery reduced down ? He has been charged with that and also kidnapping.

You can find out by asking his Criminal Defense Attorney to see if that is an option.