To summarize a response to your questions(1) Would only pay off student debt if interest rates are >7.5%... else would save money for investment purposes(2) First investment.. duplex or triplex would get you the most income (paying most if not all of your PITI payments). 

I'm mainly into short term rentals, but recently began broadening my REI exposure to learning about SF/multi-family properties. 

The purpose for doing this is varied but the biggest reason I have is to be able to give as I desire.

You have 3 main options assuming you want to keep growing.1.

The main question I ask is how long this growth can continue?

Like Michael said; is the area’s economy diversified or does it henge on one main employer.

Luckily we bought under our MOA and built in high prices purposefully on our Rehab Budget to buy safe.

@Jorge Pena the main reason to sell is because a lot of bad stuff can happen with rehabs of this size.  

I live there for almost 20 years  in the 80s and 90s  and really enjoyed it but was forced to move  for employment purposes .

@Julian Joseph The purpose of going to a Tier1 school rather than a state school is to network and make lifelong valuable connections for advancing in your career, with the side benefit of hopefully gaining a superior education.