What's behind that door, in the garage, how's the mechanicals look, is their water stains anywhere on the ceiling, etc. 

What will be your finance mechanism?  

. $30K should be more than enough for fresh paint and flooring and some other odds and ends, but if you need dry wall, cabinets, countertops, mechanicals etc it could get much pricier. 

4- of course we'd want to verify it's permitted use per zoning5- Capex will need to be budgeted for a reserve account for tax purposes6- need to get the stage 1 and 2. 7- by subcontractor issues do you mean a mechanics lean on the property?

I’m also in DFW and interested in doing a hybrid of owner/builder after the mechanical phase.

2) Are Vendor Mechanic's Liens extinguished at tax sale? 

Closeups of all mechanicals (hot water heater, furnace, etc.)

The mechanics of it.  

You may wish to confirm that the new 401k provider has experience with the particular investments in which you intend to invest your retirement funds as you very likely will have questions in terms of the mechanics (e.g. how do you invest in real estate, etc.).3.

This does not include your mechanical altitude, but I do not know those details base only on your post.This is only an opinion.