I recently stumbled upon an extremely run down home (foundation, roof, siding, mold, etc.) single family home on a nice lot in a high end neighborhood.

just from my own experience, I can see that the roof on the main house needs repair and that there could be a foundation issue.   

Landscaping , some foundation plants , mulch and the rest grass .

I think a lot of the material being put out is great stuff and can absolutely a way to learn a good foundation.

Lesson learned: 1) A Mentor, 2) Make plans; Mine are on Post-its on my closet door, 3) Practice calculating the numbers, 4) have multiple deals waiting, 5) No matter what: keep dreaming, and build foundations under them.

I'm concerned about a couple cracks in the 6" concrete slab foundation in the garage I'm now converting into an ADU. 

Regarding the comment about the subfloor, it is a ground unit, so the carpet is sitting on top of a carpet pad, which is sitting directly on top of concrete foundation.

Rear wall and part of the foundation was badly damaged. 

Me and my Ex wife's first property was a non invasive inspection, (didn't know that even existed) and we missed a crack in the foundation under the living room that took an effort to access through the crawl space.Hope this makes sense and looking forward to hearing from everyone. 

This looks structural to me, shifting of the slab or foundation.