I have no idea.
I claim no dog in this fight.
I never considered it too big a deal who deep throat was, personally and know more about it right now than I ever have - you certainly know more, I'm just posting stuff I'm seeing for the first time. ... I DO believe Nixon got screwed because he was trying to be overprotective of his staff - and that impeaching him was way over the top. I would have rather the Senate/House had looked for the treasonous leakers and stomp on them, but since that was never going to happen (and it hasn't and won't) it was ridiculous to be worried about this, and I haven't. If this was FBI leaking, as now appears possible, for whatever reason, I'm very angry they did not go this route - imprisoning the reporters for however long it took.
I imagine it possible that the reporters had Felt as a primary source, and decided they needed to hang on him a few miscellaneous items they had dug up elsewhere to throw people off his trail as well as to avoid revealing other secondary sources - and it sounds that would be completely consistent with everything but their "not a composite" contention - but right now, all I care about is using this against the Old Media louses if at all possible.
Your dependence on Felt's "denial" is completely incorrect due to Alzheimer's, by the way. Personal experience: it is inadvisable to hang anything on that interview - as you have already been told by others. It is my take that the kid throwing the "Felt is deep throat" around on the high school grounds is much more dependable - even though hearsay.
Like I say, though, I'm far more hopeful (than convinced) that this is true for a way to demean "journalists" and their "professors" and "schools" than I am for the story, now. It would also vindicate Nixon's judgement - and that, I've always respected even when that resulted in his getting fried, essentially, merely for being loyal to his friends.