Please explain "two years at 100%". Judges do not normally use that terminology. They might say, "24 months, no parole", but the length of time that the offender ultimately serves is up to the Department of Corrections and the inmate themselves. If you follow the rules and are a model prisoner, most sentences come with 15% good time granted at the time of incarceration.

This depends on the previous criminal history of the offender. If this is not their first time, they will be looking at 2-5 in state prison.

Yes, most sentences are only served to the 85% mark. Good time credit is 15% and given to every inmate as they enter prison, an inmate can only lose goodtime. On a 10-year state sentence or 120 month federal sentence, the sentence served would be 102 months. This providing that the inmate remain in good standing, not full of incident reports, disciplinary transfers, etc.

This depends on the offender's criminal history, the value of the crime (how much was the street value), was anyone hurt, was a weapon present? Along with whether they plead or go to trial, all these elements are factors in the calculation and determination of the actual sentence imposed. If you would like to offer more information, we might be able to get a bit more specific.

Depends on the charges and criminal history. The Pre-Sentence Investigation yields a commitment recommendation called Pre-Sentence Report which details the case, and the offender's prior bad conduct (not just criminal, but civil misdeeds count against you, too). Ninety days is a cake walk, I remember when i had 90 days left on a 96 month sentence.

Federal court is like quicksand. The harder you struggle to prove your innocence, the deeper they pull you. There is no way to predict the outcome of your person's case, but the feds have an unlimited amount of money and once they get their hooks in you, it is reasonable to predict a win in court - they win 97% of the time.

Without knowing more about your inmate's particular sentence, the mandatory minimum means exactly how it sounds. If the offender is guilty of a charge with a mandatory minimum sentence, the judge is pretty much duty-bound to follow the sentencing guidelines of the state. The judge does not get to interject his "judgement" if leniency is their preference, the law stops them from deviating.

This is going to depend heavily on what the facts of this crime were that came out during the trial. How badly was the assaulted person hurt? Was there any property damage?  The judge will consider his criminal history which is a big negative in this case, meaning that his priors will surely send him back.  If the "damaging" facts are light, it could be a short sentence (3-5yrs); if it's a bad set of facts it could be a long time.

You can call the Clerk of the Court of the county where the case was tried. 

The federal statute for felony gun possession is five years. Since he cooperated, they might cut him some slack but he knows he in not allowed near a firearm or ammunition, and he's been in the system so he already knows the consequences.