I own a performing duplex and have successfully flipped one single-family residence.

Still unsure about the vacancy rates but he says it has been very consistent and he currently has both units rented out with 1 yr leases (both running out end of this year) to great tenants.

The arrangement consisted of me finding the property, Remodeling the property, Finding tenants, and managing the property from that point on.

You will find it is more efficient to let a service do it rather than try to do it consistently yourself.  

Is there a way to do a market analysis similar to what a Realtor would perform if selling or buying a home?

The big thing is to be consistent and find a way to stand out from your competition.  

I have knocked on doors(a summer gig), sold cars(successfully |salesman of the month out of 40 twice in 12months| & consistently just wasn't around enough winners to want to keep at it), worked in construction (I am currently helping renovate a home in Yakima, Washington), coached high school football, cleaned carpets (straight commission) and recently started a business online and learned several programming languages (HTML - CSS - JavaScript - Ruby - and bit of Python and backend database SQL stuff) and can design a fully responsive website from scratch.

No worries about a seller sueing for specific performance.  

The good thing about holding them is that most are rented and performing.

Every city has areas that are growing, areas that are stagnant/consistent, and areas that are declining.