Essentially, we would like to supplement an income (my mother's) which is approximately $24,000 after taxes.

Really looking to supplement my current income with some passive income from SFH. 

That's another reason I am now supplementing my Bay Area rentals by investing out of state in a more landlord friendly area. 

I am normally aligned with your thoughts but we may be misaligned on this one.Offering packages may say 5 or more years for conservative purposes but many have plans to sell or refinance (supplemental loan) after the value add to realize the sponsor compensation on the sale, eliminate/reduce the preferred return, and to maximize IRR and increase the velocity of capital. 

The most modern units have resistive electric elements to supplement. 

Alternatively I could buy two cash flowing properties (say $50k each that cash flow $500/month) in a cheap area and use that income to supplement my rent.

Earn enough to leave W2 job, provide supplemental income while retired, having RE investment fund your retirements etc The ways to earn and learn seem endless.

Great rental income to supplement the mortgage but not currently cashflowing.

The $41k would be used to supplement some savings. 

I would venture the vast vast majority of BP’ers use RE to supplement their income, not replace it.