In this case, you can use Rental Income from the units that you will not be living in and that income can count to help you qualify.FHA rates are going to be lower than conventional for you almost always, but FHA does have a 1.75% funding fee. 

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. 

All the best!

The drop and Swap is about all we use here due to the confiscatory tax rates based on sale price.

It's important to know what market rents are for what you are analyzing, many properties are super under rented and you have to get them to market rates. 

Your interest rates are low. 8.5% is around the "market rate" for owner finance buyers right now...30-yr, fully-amortizing2.

I have other assets in Canada but I looking at bringing everything here when the exchange rate is better.

While less than 10% of the mortgage industry offers 40-year mortgages, here's something to factor in: they often come in with a rate increase of 20-35 bps.Assume 35 bps.$300k mortgage at 7.25% (30-year): $2,046$300k mortgage at 7.6% (40-year): $1,996Technically, it lowers the monthly, but not by much once factoring in the rate adjustment.

My absolute best advice with ANY STR prospecting is to contact the municipality in charge of regulating that area of region.

Here’s the situation:Purchase Price: $540,000Down Payment: 20%Mortgage Rate: 7.125% (30-year fixed)Monthly Expenses (Mortgage, HOA, Taxes, Insurance): $3,706Realistic Max Rent: $3,000As you can see, I’m currently short $706/month even with max rent.