At this point, I don't see how you could extract equity and keep this property self-sufficient.Selling off and trading up is probably a good strategy.

I am really open to either new construction to rent or purchasing already established property and then rehabbing them to extract more value from them.

I've been able to extract a slight premium over the competitors in my area because the properties all brand new gut renovations with nice finishes.Go to Zillow or Craigslist and see what the other units are rented for on your block.

You can manually extract area calculations from SketchUp to import into Excel or whatever to manually calculate your costs.Interior & exterior photos from the listing - We'll reference the interior photos inside SketchUp using the "Match Photo" tool, to check the 3D model and figure out where each room is located in the house.

Extract from this  the formula and throw that in an open loop feedback system where you teak your marketing effort based on your evaluation and results and repeat the process till you maximize the results.An example.

4) Am i doing everything I could to extract every value from this property?

Is drilling likely (or other mineral extraction)

Too many deals out there are filled with junk fees extracting all the profits for the syndicator, leaving the passive investor with all the risk and reduced returns. 

Make sure that the monthly PITI payment is far enough below FMR that you can extract a reasonable ($300+) monthly cash flow, once all other expenses (vacancy, maintenance, management) are considered.For extra credit, see what it would cost to get flood insurance on the property.

@Mike Callahan - if you have so much equity in those houses, can't you get a portfolio loan to extract the equity and use it to pay down the other assets?