The issue, however, is that you have to prove criminal intent.
As an example, Exxon was fined $2 million this morning for violating Russian sanctions (while Rex was CEO). It's easy to point and say "OMG traitors," but in most cases, these are just simple oversights. Similarly, if Trump sells a condo to Russians at a massive discount and violates some sanction, he can just claim ignorance and pay the fine.
You need proof that the Trumps were aware of the law and deliberately choosing not to comply. That's a high bar.
I'm also not sure if that is "in bounds" for Mueller. If he finds that Trump corp owes $100 million in fines, does Mueller actually levy the fines? Seems way out of bounds.
Lastly, do remember that Trump's businesses are large enough to be audited annually by multiple parties belonging to both the federal government, state governments, and private companies/auditors.
If there is something criminal there, it will be hard to find and we are in for a very long investigation.
I just highly doubt that a financial crime is going to be sufficient to impeach Trump, especially if the crime occurred pre-primaries. We're talking about a President that has already admitted to sexual assault.
Absolutely, but this is a criminal investigation where the audit won't stop at "oops, registered offshore" or "he overpaid for the condo" - so the scrutiny and legal tools available and utilized change dramatically versus either an IRS or private audit.