I am new to real estate investing and thinking of starting off by doing a "house hack" via renting out the unused basement as a short term rental (AirBNB, Vrbo etc) in my single family home which is used as primary residence.

Why are you trying to hide that you're renting out rooms from friends?

Full renovation with new concrete driveway and new concrete walk out basement.

Buy a large 4-5 bedroom home in a nice neighborhood and rent out the spare rooms.

I'm trying to understand the reasons....pros/cons.... to requiring occupants 19+ years or older to fill out application?

Should I also contact the owner, an LLC out of state? 

While I’m no fan of realtors, and think they are often overpaid and under qualified, the idea about not being tied down is one of the dumbest compliant’s, in literally every other line of work, you get tied down, go hire a lawyer, you pay them by the hours, go hire a doctor you pay them by the hour, and you are not being tied technically, you could agree to pay two agents out of pocket, but of course no one does this for the same reason no one pays two lawyers.  

Just to throw some numbers out there,  If it costs about 45K to rehab and rental income should be about $24000 a year.

From an investor standpoint it is very tough right now as there are not of a ton of good deals out there.

@Quentin RCollins New construction could be tricky with the costs, especially if you are just starting out.