Talk to to local foundation-friendly engineer and get their two cents ASAP while you're still in your due diligence phase.Good luck!

Why would you bring an engineer to a showing appointment?

There will be soft costs of architects, engineers, etc and of course you will need to cover the debt while there is no incoming revenue.

The time it takes a builder to work with a structures framing and CMU basement that are not plumb, square, true, flat or waterproof is more costly than rebuilding with current building codes and engineering.2) Take the time and cost you think it will be and multiply by 3 and 1.53) contractors will fail you again and again. 

Also ask if they consider importing fill of that depth/volume to be 'grading' which could require a separate permit and a geotechnical engineer oversee the backfill to ensure that it is properly compacted. 

We had to get engineering set for door design, procure lumber via specialty suppliers, then engineer how lift would work.

Additionally, in June 2022, one gallon of diesel cost an average of $5.75, a price increase of $2.50 compared to the previous quarter and the highest average monthly price increase in decades.As these material costs increase and availability dwindles, weeks are added to typical construction timelines.

Usually SFH are too small for engineered studies - I do algorithm based ones.

I am worried that the insurance will just drag this out, demanding more $1k letters, possibly engineering studies, etc.Any suggestions on what I should do?

You'll need meetings with the city, GC, architect, engineering, lawyer (for liability) at a minimum.