Valcazar, you posted a very intelligent rebuttal.
Thank you.
I will do my best not to make this a line by line quote, since it seems that is something you aren't fond of.
To catch up and answer. Not a lawyer, but lawyer-adjacent enough to have learned to pay attention to some of the details.
--You are correct that the "You know this how, exactly?" line was a comment that none of us are there and so none of us should be too confident about what Mueller and others do or do not have. Mueller has been very good about not leaking, so things really are "best guess" at most.
-- I see your logic on Flynn or Papadopoulous, but disagree about the connection to how things are happening with Manafort and Cohen. First of all, Mueller handed Cohen off to someone else (SDNY). That's something to keep in mind, when Mueller uncovers things that don't look directly linked to the original mandate, he hands those crimes off to other courts. But even if he was still doing Cohen, I don't think info from anyone precludes him slowly moving up the chain. This all feels like RICO or any other crime family investigation. You don't jump the line, you just keep moving through everyone and building the case against the higher ups. Especially in this case, where Mueller seems to agree that Trump can't be indicted while sitting, the incentives are to just keep amassing evidence on Trump and pursuing cases on everyone else around him to make the report as airtight and complete as possible. I will admit to being curious about what is going on with Flynn. The fact the sentencing keeps getting bumped is mysterious and there are too many possible explanations to confidently speculate.
I disagree about the Russians because the interference in the elections is directly in his mandate. Yes, there is very little Mueller can do in terms of pushing the case forward, but those indictments seem to be about making sure certain elements of the evidence are in the public record and (as Clara says) to keep people paying attention and show that this is still moving forward. (Also, there is the very basic idea of those cases being laid out strictly so that if any evidence later is linked to those cases and those people, it is already established that the Russians in question are bad actors concerning the election.) I'll give you "indirect", but don't think "sideshow" is correct.
Concerning the CNN story you linked to point out you think the sentencing is over the top, this appears to be all about how our prior biases and how you read the situation. I read that article, and I note that Popadopolous was up on 5 years of charges, they cut a cooperation deal. The feds are unimpressed with his cooperation level (especially his wife's public appearances it seems), and so they said "yes, we only left him with one crime, but we aren't waving sentencing for that, he should do 1-6 months." They were allowed to recommend no time, they chose not to. But they didn't go back and try to force the 5 year, and they didn't say "he absolutely should do the max". So in the end, his plea got him from up to 5 years to 6 months or less. You read it as him cutting a deal and them insisting on nailing him anyway. We will probably never agree because our prior assumptions about motivations of the Mueller team are different.
I agree with both you and Clara (Thank you Clara, for the explanation of your position) that the release of information is political in that it is being used to make targets nervous, fight back on the news cycle, and make sure people note that the probe isn't just hanging around doing nothing.
As for the FBI informant /British professor, it is a bit of a mystery and I don't think we have enough to really know here. (Honestly, I'm not convinced the guy whose name was leaked was actually the informant, since the whole incident about revealing the name was very odd.) Again, this is probably a question of priors and who we give good faith to. Sending someone in to talk to people after already being tipped off that there may be funny business involved is pretty normal. If he met with some people, asked how things were going, and reported back about some suspicious behavior, that's pretty normal. If he was suggesting to reach out to the Russians, much more of a problem. I know that reporting linked him to talking to Popadopolous and Page - both of whom were already linked to the Russians. Did he stay longer? Did he ever have a position in the campaign other than "well connected Republican guy asking if he can help"? I'm not sure we ever got the full story there. But unless we suspect he seeded the Russian email stuff. it doesn't seem to matter much. Do we have reason to suspect that? I think no, because there seems to be fair evidence the Trump campaign was more than happy to cruise for help and the Russians were already working. Again, how you interpret that will depend on previous beliefs about the people involved.
