@Ned Carey: Much of the multi-family housing stock in Boston was built during the city's peak population boom, 1890-1930 (brownstones and wood three-deckers alike), as an upper-middle class response to tenements to increase density.

Every state is different as is every city and neighborhood.  

Being out of state, my knowledge of Atlanta is quite limited, and I'm hoping to get a better sense of the neighborhoods.Are there any good neighborhood guides to Atlanta or other resources that show crime rate, population growth, home values, etc of various cities and towns nearby?

I'm already doing this the hard way, painstakingly combing through city by city, town by town, looking at gross metrics and trying to dig in.

Understanding it is a difficult market (Miami) to begin a real estate investing journey considering inflated housing prices, it’s where I currently work and I’m quite passionate about the city.

Kansas City. 

Some cities have local ordinances that require interest to be paid, but even then it’s usually a low fixed amount.

Would you guys agree that in places like Pearland, Katy, League City, and Texas City the vacancy rate is still 13%?

It is literally sitting on the edge of a small city (The Dalles, OR) and if city limits EVER expand, the property will quickly double or more in value. 

As one of the larger multi-family lenders in the city, a great deal of my clients are 2-4unit buyers/owners....many of them being primary residence purchases taking the "house-hacking" angle.