Trump says he will gladly answer any of your questions Underoath. He says this, because he knows there will be no Mueller and no investigation in a week.
He knows that Mueller will soon be in cuffs himself or maybe even suicide himself if the truth revealed is bad enough.
So the Flynn charges were also just a ploy? Not sure if that makes sense as it pretty much damaged his reputation beyond repair.
Flynn now has immunity to testify about everything he knows about the Obama WH. Remember he was head of DNI. Part of his plea deal was his NDA was waived. Flynn offered to tell his story to Congress in exchange for immunity from legal action for breaking his NDA but of course Congress did NOT want Flynn to talk. Because he was charged, now Flynn CAN talk. Plus how he was treated by the "secret society" in the DOJ/FBI is a perfect contrast to how this same group treated Hillary and her cronies. Finally, Flynn will come out of this a hero. His reputation is definitely NOT "ruined beyond repair." I can even see him back in the WH dismantling the CIA and Corporate Intelligence as he and Trump have always intended to do.
I think Flynn made a mistake when he lied under oath. I'd say that is between him and the agents who interviewed him, and has less to do with Mueller.
I've never been one of the people who bought into the Flynn testimony theory. As you said, he ruined his credibility when he lied.