@Moises Jerez be sure to schedule a demo with my support team.

I also get that light rehab vs. complete demo/gut are completely different animals.

And if this contractor actually knows what he's doing, how could he possibly think that you could demo a house without a permit?

We thought long and hard whether we should just patch it up and pretend it wasn't there, or demo everything and build it right.

I echo the above advice to make only the minimum basic repairs: fix the leaks, get rid of the mold, clean it up, stabilize it so water intrusion and whatever issues it has aren't getting worse, maybe do some demo to get rid of major eye-sore areas, slap some paint around strategically, remove trash/overgrown bushes and whatever from the property, improve the curb appeal however possible, apply turd polish liberally... whatever you can do with as little money as possible to make it look a little better, and then wholetail it like a hot potato for whatever you can get. 

You need to do the demo and check it out.

Do you have any shots of the kitchen subfloor as it looks after demo or of the tile demo process?

I'm pretty familiar with the process behind identifying what needs to be demoed and working with design professionals such as architects and engineers for proper constructability methods.I'm certainly interested in connecting and learner about this space!

The restoration company that did the initial demo and mold testing went back in for a 2nd round of cleaning.

For instance, we informed him we'd do ALL the demo.