There will have to be a support beam 4.5"x10"x36' thru the 1st floor.

Laser focus.

I had something like this in a kitchen but the solution wasn't rebuilding a wall, it was adding a footer/beam system under the kitchen floor.The order would be fix the settling first, then move on to your tile. 

Show what the bearing walls are carrying, (floor, ceiling, etc) post location and what the post is bearing on, beam size and length, etc."

we sell a lot and not all cracks are bad.Hairline cracks with no movement - we just seal or epoxy inject and go on.Cracks that are substantial with no movement we also seal.With movement on the wall we ad beams that tie into the floor and the main house to hold the wall up.with cracks in the floor with movement, sometimes you have to put a pier under the foundation.When ever there is visible movement of the wall or floor we get an engineer to tell us what to do and give that to the foundation company to use in their bid. 

Just to clarify, I am using a licensed electrician/plumber, and I did get an Beam Report from an Engineer for the load bearing wall removal. 

If you buy off the MLS this will never beam issue since the seller has their own representation.If you are buying off market you can get in hot water.

So, the contractors would have to understand all the building material needed for the ADU, timing, building codes, depth of foundation, beams and brackets to use... etc. and where they would need detail would be: on the finish work: i.e. tile, window type, flooring, cabinets (type, texture, color) etc, anything that would be considered aesthetic (as one tile could be $2 per sq ft and another would be $10 dollars per sq ft) and even choosing one or the other would entail more labor work or less and hence the labor costs could change with every decision made. 

I believe though I can't find a link that you basically need:  egress window, heat, electric, closet, ceiling height minimum 7 feet but there can be places where beams take it down to 6'4". 

The block walls would almost certainly be load bearing, so you'd need an engineer and contractor to make a plan to carry the load with beams or posts.