Generally the HOA's complete their foreclosures far more efficiently than the banks so you may have some time before they take it back. 

So far I have been less than efficient on my paint/supply purchases at Lowes/Home Depot.After reviewing my taxes I see that I spent more than 10K last year at both stores so whatever percent I can save will be substantial.

What is the most efficient way to have a Absentee Owner sign a Purchase of Sale contract from a remote location? 

Is anyone aware of documentation on the most efficient way to set up LLC to purchase property without buying individually and transferring?

I'd put that in but it was not an efficient solution for my vendor for an apartment.  

But im not opposed to adding a 2nd story if that is the more efficient route. 

You shouldn't worry about over paying for labor, just talk to some contractors and finding reasonable prices won't be too difficult In fact, the contractor is probably WAY more efficient at doing the labor than you are so I see it as less cost efficient to do it myself.

A real dehu will cost $00.02 - 00.04, run more efficiently, remove micro-contaminants from the air (hepa filter), and have the strength to shuffle around ALL the air in the basement through the filter. 

You could be a lot more efficient that way, unless you have a good reason to buy cash (like purchasing deals that require all cash).I'd do it though.

Make sure the building is energy efficient with good insulation, thermal windows, and proper weatherizing.