Yes, I think you are correct that Weisman was working as “General Counsel” for Mueller at the FBI during the time of the Uranium One scandal.
https://en.wikipedia.org/wiki/Andrew_Weissmann
Rosenstein worked for Mueller as far back as 1990. He was primarily known for being the US’s Attorney for Maryland, where he worked until being appointed Deputy AG under Sessions.
https://en.wikipedia.org/wiki/Rod_Rosenstein
There’s really no way to predict how this may turn out yet, and many may be adjusting their positions along the way. But people should be judged by their fruits, and Mueller, Rosenstein, and Weissman all have very questionable backgrounds, and all very well could have been involved in the coverup of Uranium One, if not other notorious scandals of the day.
Here in the present, we see multiple Trump associates arrested, yet not one from the Clinton orgs, or the DOJ that was protecting them. Hopefully that will change, but with an Attorney General who is recused from actually investigating any of it, by choice, the chances of actual arrests of the Clintons or the DOJ would by extension be lower, just by nature. So we have to keep the pressure up, and not listen to those claiming it’s all already in the bag, because that usually means they just don’t have to fortitude or capability to actually keep up with it, and are just hoping someone else will take care of it all for them.