I'm currently with an investment brokerage but my end goal is to be an investor and feel the big shoes my parents are leaving me with! 

We ended up just selling our 4plex, but out of the three, I liked heart and home best.

The main issue I have is contemplating the baloon payment at the end of the 2nd year and refinancing the remainder with a bank...how can I compute that into calculating the IRR?

The advantage of Reg D over relying on the general exemption is (1) if you comply the SEC can’t come back and say you should have registered and (2) if your sued by a disgruntled investor you have a definitive defense, which means an attorney is unlikely to take an investors case on a contingency basis - unless fraud was committed.  

I don't see any sense of urgency from you, so no one adjudicating this case would either, or end up taking any action!

I started off with house hacking a duplex in Malden a few years back and have been able to acquire 14 more units since then.

We try to have all of our leases end in March-June so it is easier to lease the property in the spring/summer.

That also plays a major role in what to do. end of day stocks and real estate over time provide the same return on average - so it is really based on the individual, their experience and desire Thank you. 

So your son is wholesaling the property then, it sounds like, and sellers are willing to sell subject to the existing mortgage to the end buyer?  

Had an issue with trying to self-permit a build a few years back that was an HPR but had an "A" and "B" designation.