2scents.
a. He was NOT “officially accused” of discussing sanctions with the Russians, since there would have been nothing wrong with that. He wasn’t “officially accused” of anything; in fact he had no idea it was even an official meeting. He thought the FBI agents had come to discuss the transition with him. Agav urcha they asked him whether he had spoken with Kislyak, and/or what he had discussed, and according to them he denied the conversation. We don’t know what was actually said, this is only the agents’ report, composed much later.
b. See above. The conversation was, eventually, about his phone call, and according to them this is how he described it. Their impression was that he was not intending to deceive them, he simply wasn’t being exact.
c. The lie he was charged with was this conversation. That he had denied discussing sanctions when in fact he had discussed them. Had the conversation been conducted according to protocol, it should first have been cleared with the DOJ, Flynn should have been told he was being questioned and had to tell the truth, he should have had a lawyer, and above all the transcript THEY HAD should have been provided to him to refresh his memory. They did none of this because the whole point of the conversation was to trick him into telling a lie so they could charge him with something.
d. It is literally maasiim bechol yom that people plead guilty to things they never did. It’s a huge scandal.