You can pay his bond as long as you have not been ordered against doing so... 

Released without a cash bond... "on your recognizance" 

The bond for your inmate is probably going to remain at that amount because of the "failure to appear". The bond assures the Court that he will appear going forward. If he paid the bond as was released AND then failed to appear, he would lose the money and his freedom.

Usually not. it would have to be a very slight violation. Magistrates HATE seeing an offender violate in any way... makes them think the person that got an early release really didn't deserve it. 

Non-violent offenders are treated for bail similarly to all defendants. The magistrate assesses the crime, the criminal history, the size of the loss, and potential harm to the public if released. If it is determined that all of the criteria is benign and there is no risk that the offender will appear for their court appointment, then there is a chance that they will be ROR's (released on their own recognizance) 

No, the bail bondsman has nothing to do with anything except "guaranteeing your court appearances". The old warrant will be served by the jurisdiction that ordered it. You might have to get a second bond.

That revocation will cause the judge to take their time to see him. With his bail revoked, he will be in until they are ready to hear all of the pending charges. 

They can hold you on a "federal material witness warrant" pretty much for as long as they want. While they are holding you on that premise, you can bet they will use the time to build their case.

The short answer is "ask the attorney WTF happened". If what you are saying is true, the attorney dropped the ball, big time. But, most times there is another side of the story. The prosecutor probably presented some alarming fact-based theory where evidence or affidavit has given them the tool (with the magistrate) to get a no-bail hold on an individual.

You can call the Clerk of the Court in the county where they caught their charge. The desk person has all legal information related to criminal and civil cases.