I believe that the Federal Reserve is going to cut rates by 25-50 bps at it's September meeting (no emergency cut), but that 30-year fixed rate mortgage rates will rise to upper 6s low 7s around the same time, and Commercial borrowing rates, including for multifamily, will increase as well. 

If she lives rent-free, you retain control of the property but lose the ability to claim rental-related deductions.For long-term planning, consult a CPA and attorney to ensure compliance with tax rules and align ownership structure with your goals, including potential conversion to a rental or estate planning considerations.

Many people don't realize that you gain as much or more net worth through debt pay-down, and while it's less liquid than cash flow, over a 5-10 yr hold period it's considerable if you buy in the right areas with the right asset class.

Some costs MAY qualify as startup costs if the rental rises to a qualifying trade or business level under 195 as well.

There are other ways to legally raise capital, however, they have some inherent disadvantages making them considerably less desirable for what you’re trying to do.   

Yes - I spoke with Ivan Barratt several years back many times over the course of a year, and put considerable efforts into due-diligence.

Every property up for consideration gets a visit.

They do not take into consideration the revenue from the STR business as part of the selling price.So if comps say the duplex is worth 500k, then it is worth 500k.

Over time, as rents rise the property could become even more profitable.

These are all important considerations, and understanding the requirements can save a lot of headaches down the road.