But, in the end RR does not have the right to authorize anything beyond the Trump/Russia connection. Anything outside of that would have to come from Sessions, IMO.
The way I view the split of authority and responsibility is through the lens of Sesions' recusal, which says NOTHING about Russia.
Sessions is recused from investigating, exonerating, or prosecuting the Trump campaign, because he (Sessions) was a primary advisor to that campaign.
If there is a case against the Russians for meddling in our election, not in cooperation with the Trump campaign, Sessions is NOT recused. But ehre is Mueller, with his case against the Russian troll farm.
If there is a case against Manafort for tax evasion involving Russian money, Sessions is not recused from that. But there is Mueller, with his case against Manafort.
Mueller's case agasint Flynn has other (serious) problems, but at least Mueller can claim it had to do with the investigation of the Trump campaign.