IMO, that is house hacking into a newish multi, and leveraging the lender's money by taking advantage of 3.5-5% down payment. 

Your payment is the same every month and the lender will collect more interest in this format because the borrower is paying interest on the entire loan amount from day one.

The property taxes stay with the property and neither lender would be responsible for them, the new owner would.

More important is the equityMany people will overpay to get a home on seller financing then realize they overpaid and cannot refinance because a lender may want 20% equity which could be a tough hurdle to overcome in the future if prices stay stagnant and you have a balloon in say 5 years.

The lease (with the current college students) was just renewed through their 2025 school year.I'm trying to figure out how to make this happen with little-to-no money down, as I have other 'irons in the fire' at the moment.I'm planning to offer $400-450k for the home, and am trying to structure something where a conventional lender would loan an amount that would be covered by the current rental rate (lets just say $300-350k)...   ...then, anything outside of that amount, would be carried by the Seller (for a short while)...   ...Seller financed with a ballon in 5-years?  

You should have an attorney review your contract and all communications to determine your best course of action.

Many lenders will not do a DSCR loan unless cash flowing.

Many lenders don’t want to discuss fully until I have a building permit. 

So, I'm helping them hunt for a private money lender or some other source they may be able to utilize.

It's very easy to get into a situation where the lender, property manager, and the insurance agent are all profiting more than you.