Goal is cashflow or at least covering a substantial portion of the mortgage. 

As for non-bank loans, I'm familiar with a loan program that provides 100% financing, but it requires a minimum 650 credit score and proof of funds covering 12 months of interest.

I'd recommend looking at costs. your build cost is going to be well over other homes because of the fixed costs like slab, Hvac, roof, etc. check the market drivers and weight the benefits of short term versus long term. long term is no furniture and help pays mortgage but at this size it doesn't really cover everything. we didn't find a lot of economies of scale in single family detached. can you build more than one unit?

These properties cover my mortgage, allow me to save for maintenance/repairs, and are projected to be worth $7–9 million by retirement.

Since you won't be able to recognize it as a valid rental if you're charging under market rent and you also expect to be covering any house expenses that are outside of her budget, this seems the best choice. 

Does this exist in the commercial realm?

We just acquired an existing duplex in Fort Lauderdale and planning on tearing it down and build a new duplex instead.

Cover my basis and send to the rental and the 2 addresses the one tenant provided via text? 

Then any rental income you could obtain from that property could be used as an income source for loan pre-qualification.

– Considering Class A properties with established tenants• Less focus on appreciation – Prioritizing income stability over potential future gains Current Opportunity: I’m evaluating a retail property in downtown Portland with:• >80% occupancy, most tenants in place for 10+ years• Decent cap rate (6-7%), NNN lease• Well-maintained, high-quality building, with existing HOA which will take care of maintenance.