I kept telling every landlord even if your place is brand new, rent is way lower since 2015.

., tear out to studs) to be livable by lower middle class standards.

His current annual debt service after refi is significantly lower than what his annual lease would be years 1-5 with 3% annual increases.

I refinance my current loan, an FHA, into conventional (my FHA is at a 3.35 APR...hard to beat) at a higher rate, PMI will come off, and then the loan payment may be the same or slightly lower by $50-$100, and then immediately use FHA again to buy the new property, which is a four unit property. 

We were even offering a bonus to buyers agents, we often do on lower priced stuff.

I put in $800 (a new fridge and stove for lower unit) after closing.

And it’s not a grant, it’s state specific  first time home buyers mortgage program that is offered with lower pmi and interest than others in the area and it did require owner occupancy.I only ask because the area where I bought isn’t the best but isn’t the worst if that makes sense.

The lower unit needs work (about $12-15k) but can be converted to a 3-bedroom unit.

But I think you're causing yourself unnecessary stress by looking at these (admittedly complex) issues as things you have to solve from the ground up.  

Getting into higher end for putting in lower grade product.