This is not my area of expertise, but my conversations with friends who are more familiar with practicing within the federal court system have led me to believe that the withholding of the evidence you mention and failure to make certain disclosures open up the possibility for Flynn to withdraw his pleas even at this stage. I'm sure you've heard people mention fruit of the poisonous tree doctrine in regards to this case and it seems clear that the entire case is tainted by how the Feds have handled it.
Like you (I'm assuming), I want to see General Flynn not only vindicated but held up as the courageous hero he truly is. A pardon from POTUS is just not going to be enough in this case.
Not sure if you follow the Dilley drops, and just mentioning them here can get you filtered, but he has said some interesting things about the Flynn case. His "source" says General Flynn will not only be fully vindicated but will become super rich after winning lawsuits against the government's (difficult to sue individual agents of the government who often have immunity in such cases) handling of his case. (See "witch-hunt") I sure the fuck hope so!
Wish I could be more help but trustworthy details are hard to come by in the case where misinformation is around every corner.
Anyways, long live Flynn, Rogers, Trump and Q-team!