I've read a few posts from fellow BPers in the area and they've all got right margins as well.

A potential tenant that is willing to rent an apartment with marginal income is not demonstrating good fiscal responsibility. 

If 1 hour of your time spent imparting knowledge, helps you realize a greater profit than 1 hour of your time spent practicing what your teaching, you are simply validating that your knowledge is more valuable in theory than in practice.   

You have to make sure on these sale leasebacks that the business is still on an upward trend and profitable.

These types of properties are where huge profits are made.  

I’m wondering what kind of profits can one see coming from a 4 unit?

If it gets too bad, I’ll consider other options, including converting to condos and selling them for a profit.

Because I am a bit older (late 50's) I was hoping to cash flow with a 15 to 20 year note so as to quicker build equity while still being profitable. 

It'll be impossible to be profitable without raising the rents substantially and cutting your expenses.

You could use a "cash rich" Partner to help you by taking part of any profit.