If there was a minor hit and run and the person at fault left, what could happen?

You can not lie.  It would be perjury.  Perjury in this case would probably be a misdemeanor.  But it can be punishable by fines and/or imprisonment, depending on the jurisdiction. 

In most states the owner is vicariously liable for the acts of those to whom they entrust their car.  In other words, with permission to drive. The fact that you gave permission to someone not allowed to drive at the time could also be a fine for you.  For the driver, it will be much worse.  You did not fully explain the probation issue but as for the license being suspended, it could be revoked. 

Seek legal help in your area to cooperate fully with the police.  Good luck.

A hit and run is a felony or misdeanor depending on the seriousness of the accident.  It does not matter whether the acciedent took place on public or private property.  You should also be concerned that lying to the police is a crime and you can be prosecuted.  I suggest that you be honest with the police as to what happened becasue you do not want this incident to ruin your ability to have a license or get one as well as have a criminal record.  Having a criminal record will prevent you from obtaining jobs and getting into school.  Your friend needs to be honest and obtain a lawyer to help resolve this matter.