There is inflation protection and an endorsement to add 25-50% of additional replacement cost in order to protect you from unexpected inflation (like that of lumber in the last 2 years) but it hardly effects premium and does not effect the deductibles.

Sean O'Toole was interviewed by Bruce Norris on The Norris podcast and Bruce highly recommends Sean as well as his site and for me, a Bruce Norris endorsement is enough for me. .George

Would never happen, they must perform.Thanks for hearing me out :)In my experience, a mortgagee's title policy runs two or three pages, a Schedule A and B possibly a C, the Terms and Conditions and Exclusions from Coverage are printed on the jacket cover and perhaps another page or two for endorsements. 

The ALTA 9.2 is an endorsement to be issued to a policy which provides additional affirmative coverages to a standard title policy. 

Caroline Gerardo  NMLS 324982 This is not a endorsement of Attorney Opinion Letters but have you used them?

There is this new bill/legislation from WH that WH is trying to endorse more ADU building.

This is not an endorsement.

You will want a Rehab policy that includes a builder's risk endorsement during rehab.

The insurance company may be able to endorse the policy to ensure continued coverage.Forming the LLC and bank accounts (From your post, I think you did this one): Establish an LLC.

They are essentially endorsed at the bottom of the city of San Jose website - https://www.sanjoseca.gov/business/development-services-permit-center/accessory-dwelling-units-adus/adu-permit-plan-review-process/adu-single-family-master-plan-programwww.abodu.comwww.prefabadu.comwww.actonadu.comFrom a cost prospective, the prefab ADUs may be the way to go but I share your concerns about issues with the structures in 5-10 years.