In another post I had written, a comment came up in regards to Mueller not indicting a sitting President. It is my understanding that, in the end, Mueller does not have to indict him in order for Farkwad to be impeached. I believe that Congress has the ability to impeach him without Mueller’s indictment. The issue is that Republicans hold both houses of Congress. I believe that if Dems could take the house and Senate, Farkwad would be impeached. This seems to be a consensus as the Republicans are starting to sound the alarm in their mid-term campaigns. But here’s some info on the impeachment process and why I say this. [litigation.findlaw.com]
It reminds me of the story of Trump's impeachment [lawrina.com]
Your understanding is correct. Mueller will issue a report to Congress in which he will spell out the provable offenses by Trump and provide the supporting evidence. It is then up to Congress to impeach, built on the report. That is why is absolutely essential that the 2018 election turn the House Democrat -- so that they will act on the Mueller report in a legal, moral, and patriotic manner.