Unlike informal probates in Hennepin County, proof of death documentation (e.g. a death certificate, an obituary, etc.) is not required to be submitted when filing for a formal probate. The reason is that the petitioner proves up the petition in court, testifying under oath the facts of the decedent’s death.
As a result, the proof of death requirement only applies to informals in Hennepin County. As far as I know, no other county in Minnesota has this requirement.