This causes my note to increase a few hundred dollars a month but will not have to put money down for closing and instead leave with cash in hand.

Generally, shipping containers are used as a way to expand an existing self storage facility with minimal capital outlay (the containers can be leased) and as a way to increase revenue without improving the property that would generate an increase in property taxes. 

The Heights is where you have a good chance to find one due to relatively consistent construction through the last 50 years on parcels of land that (at least started out) at a decent size, not those subdivided postage stamps in Rice Military. 

I've been back and forth with her on the phone consistently for the last week and half about everything and I know she has no help.

I mean if you happen to have an extra $20,000.00 to play around with it might be worth gaining the experience if it can provide you with a new strategy for forced appreciation or increasing the expected rental income. 

With the location on the edge of an improving and re-developing downtown, does that increase the value of these proposed new homes despite the existing ones?

There are several different neighborhoods with varying rent prices and also varying year-to-year(YTY) rent increases.

Most likely she wants a two year lease to avoid a price increase, and is happy with where its listed at now. 

If you got a couple more quotes, it might really increase your cash flow. 

If you are going to rent the lot and buy the home you may find your expenses increase.