Most of the harris county properties at the price point (and a bit higher) its highly likely that you will end up getting an empty lot with a run down building which may or may be there by the time you make acquisition (i.e. city already sent notice and may demo it for you) ...i would take that 30K and find a rehab house and use hard money to buy and your funds to repair and refi to take all cash out and start renting .. 

The first one they want someone with plans to demo house and build a new house on site.  

That’s what I saw you had to do from their demo video.

Without knowing your area or market this is where i would start.Maybe the lot had a house that was demoed.

I ended up demo-ing the stairs (after paying a fee for a demo permit $75) and getting some foldable steps that ppl with RVs use to make stairs that can be packed up to go. 

Not much you can do to keep them from spreading between units unless you were to demo your walls and seal the party walls against rodents.

Demo, Frame, Rough Electric, Rough Plumb, Insulate, Sheetrock, Tile, Exterior Trim/Paint, Plumb Materials, ...

If it's really old we just tear it down and figure in demo costs with purchase price when we acquire it.It's common regardless what the lease says for options for tenants to ask for concessions.

But if I have to completely  demo the addition I'm sure it'll cost way more than $60k.

We started the demo face but had to stop and wait for the architect to finish the plans and submitted to the city for permits.Update 11-15-23: The Master plans has been approved by the city of Miami.