., "I will buy at least one single-family home, duplex, triplex, or fourplex before the end of 2019") and then do it.

Getting into multi family in PHX is a bit of a high barrier to entry and the number of options you'd have are super low. 

My partners and I (3 of us) are based in Miami FL (not the easiest market at the moment) we are all realtors / brokers and investors, each have 20+ years of experience down here, have done multiple ground up single Family and duplex builds and currently have a portfolio of single fam and duplex properties.

I recently participated in the Howard county tax lien sale and have a property that I can now start the foreclosure process on.

Treat your family private lender like (or better than) any other private or HML: promissory note and lien recorded against the property.

North of the River tends to house single family home bedroom communities.

Personally, i dont have any family here in Boston, just college friends, who will graduate and go to different places or back home.

Quote from @Stetson Oates: For example, your 16 year old rear ends a family of 4.  

Louis Fed shows the delinquency rate on residential single-family mortgages, and proves there's a way to spin this data to show that delinquencies are increasing rapidly.

Investment Info:Single-family residence fix & flip investment.