I have been deliberately managing it as a rental (ie, contract, collecting rent, etc.). 

The good thing about househacking a legal multifamily unit is that lender allows you to use the vacated units of 75% market rent as an income to offset the potential current mortgage.

Will share a similar update on mine when under contract. 

My recommendation would be to put the deal under contract, then during your inspection period talk to everyone and anyone that is local that buys properties like this and ask them if they know the property or anything about it and ask them if they think it's a good deal.

An LLC does not provide much legal protection, it acts as a legal firewall to separate assets.

A non conforming unit is technically legal but it doesn’t meet current zoning (but possibly was once a legally functioning unit as a residence).

Right now interest is in the 6 figure.I spend a great deal of time on it with the contracts and accounting . 

Regarding number one, while it may or may not be legally necessary (not sure), I think it's a good idea to have a separate account for each entity.

Generally there is consensus that DSCR Lenders can only offer a 1% prepayment penalty for up to 3 years in MI, but some lenders have recently reportedly been flaunting this rule - I would just tread carefully here in this area, generally not advisable to get potentially tangled up in a flawed legal doc with a non-sophisticated or fly by night lender

The new law in Oklahoma for wholesaling activity called "Predatory Real Estate Wholesaler Prohibition Act"states  that an equitable interest (a wholesale or assignable contract) can not be PUBLICLY MARKETED as shown below.