As long as the misdemeanor is punishable by two years or less it is not a "crime punishable by more the a year in prison."
Congress excluded expunged, pardoned, or set aside convictions as well as convictions for crimes defined as a misdemeanor and punishable by two years or less.
As to the effect of the change in judgment that is a matter of state law. Would the state courts still consider her to have been convicted of the felony? In some states such action has the effect of completely wiping out the prior conviction as if it never happened.
While on probation she will likely be a prohibited person. Most states consider people on probation under a severed adjudication to be convicted for most purposes because they have operation guilty. It is not until after probation is complete that one would no longer be prohibited.