Price just went up. 3 teddy bears now.

I do not know the exact rules because I secure all trenches but - and this also depends on the soil - the looser the soil the more shallow you need "shoring" If it's more than a 3-4' deep take care and slope the sides- the deeper you get you need to secure the sides.

Also, has anyone done grading before of the soil around the house?

"Moisture and dirt are entering the basement near the stairwell""Additional support columns/beams lack visible hardward securing them into place"Engineer noted there is no structural component dug below freezing level on any of these supports which would need to be done to get the foundation supports to code"Signs of water penetration noted on the basement walls"Picture showing proximity of nextdoor house"The soil slopes towards the foundation, or is flat, and must be corrected to prevent water from finding its way to the foundation" (This is the side of the house with the failing retention wall in the basement and has extremely limited access) The engineer recommended potentially just paving cement between the houses to seal it and recommended against a french drain as installing it would go below the level of the foundation already.  

Is your soil the type that tends to "Settle" after the line is in, requiring a re-dig and an adjustment to get rid of bellies in the line, or is it considered stable.Are you allowed to oversize the line a little for a small upcharge?

Whether or not the owner lives in an “illegal” apt has no bearing on enforcement. 

Whether you use that one or not has no effect or bearing on the turnkey company, they don't make commissions or anything like that by you using that one.

Soil samples and tests?

Here's a qucik mockup of the garage more matching the house.That foundation, wow, what a mess.If it were mine I would have a structural engineer and maybe a soil engineer come out and give an opinion on it.It's sheer weight may have made it crack off like that, no rebar, etc...If it's was salvageable, maybe I would jackhammer away the broken parts and reset the walls on the good part. making the garage smaller.Disassembling and bracing one wall at a time and increasing the overhang of the roof.Then when done, gypsum board the entire thing inside and paint it ceiling white.If it were  my personal garage I would Pink Panther insulate it and use a space heater for winter comfort.It could be a nice little gym for renter who works out.Also, I would have an electrician verify the electrical is hooked up correctly for garage (because the concrete seems amateurish I suspect the electrical may be too).

@Jennifer Thomé it’s not quite apple valley but I have STR’s in big bear 45 minutes away and they have been insanely good for my wife and I.