In need of civil engineer

Thank you in advance for your time, We are an ADU manufacturer and have a project that needs some assistance. At this time, we are looking to establish a long-term relationship with a company that can assist us in multiple ways (Geo, Civil and possibly Structural) , Now and into the future. We have not obtained a soil test nor is our Autocad drawing an actual print that can be turned over for concrete pass. Second: is if you have time to review the attached project and advise on whether we should pour footings to increase the strength of the existing retaining wall (obviously it's hard to make that determination without a soil test) A contractor advised that since approx. 80% of the pad is on native soil that there would be no need pour a retaining wall. I'm curious if you see any inconsistencies in his statement. The attached (in the link below) photos show the proposed location of the slab on grade, In the photos you can see the previously installed retaining wall. Our concern is that this retaining wall is not strong enough to do its job if we pour the slab in its proposed location. (Marked by black stakes) Attached is a Pdf of the Proposed pad. [login to view URL] Again Thank you for Your time. looking forward to hearing from you .