Do some deals get some experience, make some money, and build your balance sheet.

BUT if it gets your deal done with less cash out of pocket, might be worth considering a higher rate until you can build some more equity/ pay down some of the balance, and the refi into something more reasonable in terms of rates.

So rent for now.Own the debt until that balances--yes the underlying house price may go up, but that's fine you're also more equipped.

The balance needs to be paid by 5/31 before it goes in foreclosure.

Balancing that with your new duplex mortgage payment and your plan to refi when rates go down is a solid strategy.

Hi - typically Mixed Use properties are going to require a traditional commercial real estate loan from a bank, small balance commercial private lender or for the larger ones a CMBS style loan.However, a newer "DSCR Loan" product for Mixed Use is making a comeback - which is a really great option for smaller properties/more beginner investors since it has all the same trappings as a residential DSCR Loan (30-year fixed, easy qualification, straightforward process) for a property with commercial units.Generally going to be limited to 8 units max and has to be primarily residential in every way (majority residential by units, square footage and rents) but if it fits all that, its a great option

Defining your goals will help determine the best strategy and ensure it aligns with your current means and long-term plans.By taking these steps, you can balance your ambitions with your responsibilities, reducing risk while building a successful investment portfolio.

You would likely use the proceeds to pay off the HML, leaving you with a new mortgage (which you paid to get) and a HELOC payment (and possibly a residual balance with the HML). 

My plan is to assume what his balance is as a subject to and possibly paying cash over as a seller finance and meet the payments by tenants that are in place.

You'll have to balance cost vs features!