If you are currently renting, I don't see any alternative aside from house hacking where your monthly living expense can be turned into an investment. 

I would be househacking my first property whether it's living in one of the units for a year while renting the other side simultaneously or living in the entire home for the first year and then renting it afterwards. 

Will you be able to to get proforma rents? 

Therefore you won't need to qualify for REPS status. https://www.therealestatecpa.c...Here's the section which is most relevant to STRs of 7days or less (or 30 days or less with substantial services):"If you rent a property to customers with an average stay of 7 days or less, on average, this is a short-term rental.

These people rented it through AirBNB. 

I recently found a property on Zillow that looks to be in good condition (built 1940s) and has a finished basement that could be rented out as a Mother-In-Law unit (separate entrance, kitchen, and bathroom) while my partner and I live upstairs.

Rent-to-own, or something?

Although in the next few years I'll be starting a family and will want a single family home, if I put in the work of finding off market / on market multifamily deal the medium term rents could be insane. 

Consider all the things that could go wrong and see if the lease addresses them: unauthorized pets or tenants, early termination, security deposit, lease violations, late rent, eviction, lawn maintenance, parking, etc.5.

It's been steadily growing in terms of population, rent rate and appreciation.