Correct me if I'm wrong, but I think Clean Hands Doctrine would also be in play, would it not? The De Facto Officer Doctrine exists to protect those who were innocent of the deception from unjust harm that would have befall them if the officer's actions were voided, but the Clean Hands Doctrine would imply that those who were in any way a party to the deception would not be entitled to such protection.
The clean hands doctrine is a principle derived from equity jurisprudence and you are certainly correct that if someone who was in on the deception tried to benefit from it a court would have the power to prevent that.
For example, let’s say the chairman of Solyndra was in on the birth certificate scam and knew that Obama was ineligible, it may be that any financial benefits to him from Obama’s official actions could be rescinded.