I have a SFR with a septic and make sure there is language in the lease/rental agreement that scares the %$#@%#$ out of the tenant concerning their abuse of the septic and I make sure they understand it and initial next to this language.  

Your purchase price is the number you would depreciate it at.You bought the property for $70K, being conservative, I would do the ratio at 80/20, building/land respectively.I do not know how much your initial mortgage is.Assuming this building is residential, you can only depreciate 80% of the purchase price and straight-line it for 27.5 years. 

Lately I have been purchasing land for the purpose of building duplexes so the land deal initially is pretty straightforward.

Is a private or hard money lender not the best solution, if we lack the initial capital?

Assume 70% LTV (I have never done that low LTV on an initial purchase but it helps the Midwest case) but it will not matter as the ROI will not be close.An example: duplex (4/2, 3/1) purchased in 2012 met the 1% rule but in addition I got a great rate so it would have cash flowed good at 0.65%, purchased for $302.5K with 80% LTV. 

So maybe the extra cost of private money needs to be factored in to your business plan proforma initially.

As mentioned before, watch out for unexpected large expenses that might have been overlooked on the initial walkthrough.

My focus initially would be residential. 

My initial goal is to reach 40 units @ 100$ net/door minimum.

Initially my strategy will be wholesaling and grow from there.