I will be doing flooring, drywall, electrical, kitchen, bath, and windows and based on your suggestions I will prioritize the work of what will be done first starting after the demo and go from there for a logical breakdown of how the work will progress and how to attach a dollar amount to it.

Personally, I'd look at it as a building lot, less the cost of doing a complete demo, for purposes of buying.

Like others have stated, demo is going to be a hefty cost, and it sounds like (assuming you go with a 4 inch thick slab), you'd be looking at about 9 CY of concrete which should be around the $1,000 range if you want to get the big concrete trucks to pour it out quickly. 

Home Depot also has demo classes where they show you how to do things like drywall patches and tile work among other things.

To stay on top of costs to rehab here, we are very surgical in the demo so we can't use "neck down guys".

It’s a non conforming lot”I say “I know on a duplex or a triplex the town can make these non conforming multi families conform and become one unit structures, but I doubt they can make me demo one of the houses.”  

@Nadine Perry    Always good to go to the sale and observe...take your list, see what your Maximum bids would have been, and see if you would have won any with your max bid.If you're going to Harris county there used to be a lady who would give a brief overview of the sale maybe 1/2 or 1hour before the sale.Not sure if it is this lady or not....or even is she still does it.There is also a group called RAD that might show up and give a brief overview, just in case you see shirts or signs.Here is the guide to Harris County.....it is a little different than other counties due to number of properties and size of the county.https://www.hctax.net/About/An...They don't have one big sale, but split it up by Precinct....I believe 1,2,3,4,5,6,7   so essentially 7 different sales.You may have work to do with your title company to get some liens removed if there are any...like mortgages.Governmental liens like IRS, Treasury, city liens, code compliance, demo liens things like that typically don't fall off and can't be negotiated...you'll have to pay those in most cases. 

Or, if you already plan on demoing and major reno, I would advise them of that, and allow them to vacate at any time with no penalty, and no cleaning required.

We are looking into possibly demoing the whole thing out and installing a premanufactured home 3/2 to take place on it and rent it out to a nice family. 

@Adam Hamilton I am in the process of getting our real estate business set up and would love to see a demo of your software.