There is not a lot of guidance in the case law regarding the impact of a presidential pardon on the payment of fines or imposition of forfeitures.
In 1995, the DOJ Office of Legal Counsel opined that where a criminal conviction was accompanied by a restitution order and a presidential pardon was given, the pardon would undo the restitution order to the extent restitution had not yet been paid to the victim, but if the restitution had been paid, there could be no recovery of it after the pardon. That opinion did not address fines and/or forfeitures payable to the government.
When Bush commuted Scotter Libby's sentence he specifically stated that the commutation did not extend to the fines that were imposed on (but had not yet been paid) by Libby and, in fact, Libby had to go ahead and pay those fines. But implicit in Bush's excluding the fines from the commutation order is the notion that Bush could have, had he chosen, cancelled the fines or, possibly, ordered the money returned to Libby if it had already been paid. (When Trump later gave Libby a pardon, his statement referenced the payment of the fine but did not indicate that Libby was entitled to recover it).
The terms of the plea agreement between Mueller and Manafort raise additional questions about the status of the forfeitures. In particular, that agreement states at one point that "Your client understands that the United States may institute civil or administrative forfeiture proceedings against all forfeitable property in which your client has an interest, included the Forfeited Assets, without regard to the status of his criminal conviction." That language might be read as suggesting that a pardon relating to the criminal conviction does not impact the right of the government to institute forfeiture proceedings. Other language in the plea deal seems to link the forfeitures to the criminal charges and guilty plea.
So the answer is, we simply don't know.
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