Hey Allen,I can see that you have put good amount of thought into your plan.

If you bought the certificate from the state for the full amount quoted to you, you must contact the state and get the calculations of how they arrived at that number.

They are known as the Winthrop Factors-The purpose for which the property was initially acquiredThe purpose for which the property was subsequently heldThe extent of improvements made to the propertyThe number and frequency of sales over timeThe extent to which the property has been disposed ofThe nature of the taxpayer’s business, including other activities and assetsThe amount of advertising/promotion, either directly or through a third partyThe listing of the property for sale through a brokerThe purpose of the held property at time of sale; the classification as an investor or dealer is determined on a property-by-property basis.To me intentionally buying a property to renovate it to resell it for profit, twice in the same year, and opened an entity to do it in ....is going to be ordinary income and not capital gains. 

@Timothy LinYou will see two main ways of calculating cash on cash returns:First, is what I call "annual cash on cash":  Annual distributions divided by amount invested. 

One way to maximize your rental revenue is talking with Property Managers in your market to get a rental analysis to see if you are maximizing the amount of rent you are getting from each unit. 

Because you are essentially buying into an existing business, the sale of it could generate a disproportionate amount of tax for you given your time in this deal.

What is your price range/down payment amount?

If you are looking for turnkey properties, buying at or below lender LTV will likely not be possible because you are paying for someone else's value add/profit. but if you are adding value(Buying distressed) and adding your own value, then your possibilities open up tremendously.The mission is to limit the amount of cash in the deal. 

With some more math, you’ll see that the extra amount in dollars is not that much compared to the total amount of interest paid.

From the brief amount of research I have done I think the first action I would take would be in the direction of Househacking.