This is a very desirable part of town and the tenant pays well below current value for the space.

The precipitating factor was this couples adamant desire to purchase the property which allowed me to negotiate a price that, after discussing with my realtor, I feel meets or exceeds what I would get if I listed. 

I desire to approach Buy and Hold via Brandon Turner's term "house hacking."

I found out to not use national banks as their deals don't particularly favor my desires.

However, cuts to classrooms may alter current demographic trends and make Chicago less desirable than it is now.  

HelloI recommend to start out without using no money ...zero dollars..If you have the drive and desire to make this happen you can do it...Below is a link to a ton of free information...http://www.flip2freedom.com/

If/when somebody buys the community I'm thinking this lot may become desirable to a builder?  

Depends on your desired annual return and how active or passive you want to be.Also if you have 10,000 to start or 1,000,000 etc. 

Some markets are more desirable (say where you can rent a home for 700 and the lot rent portion is 300, and you have a good spread).  

A 15 grm is not a very desirable number Smaller is better in grm terms