I excavated and set grades for footings and prefab walkout basement.

They basically hold the building liable rather than the owner and that liability transfers from owner to owner until someone deleads it and breaks the chain. 460.100: Duty of Owner(s) of Residential Premises (B) Whenever any residential premises containing dangerous levels of lead in paint, plaster or other accessible structural material undergoes a change of ownership and as a result a child younger than six years old will become or will continue to be a resident therein, the new owner shall have 90 days after becoming the owner to obtain a Letter of Full Compliance or a Letter of Interim Control, except that if a child younger than six years old who is lead poisoned resides therein, the owner shall not be eligible for interim control, unless the Director grants a waiver pursuant to 105 CMR 460.100(A)(3).

"Be the general" is good advice, but the general has to pay (or get someone else to pay) his foot soldiers. 

My family had rented a 3000 square foot home from 2016-2020 with two large mastiffs.

The plan is to get a pre qualified buyer using the USDA loan which will pay 100% of the cost for the buyer but the developer would need to use there resources to foot the build after finding a buyer.

You make a very good point and I was thinking that I might tunkey or house hack to gey my foot in the door as well.

Have talked to a few contractors and am getting wide range on price per square foot.

I may be different with new builds as we look at pretty small units.Here is how the $ per foot broke down in the Eugene new build:  that's $3.06 vs vs $2.55 vs $2.01 per foot for studio/1 bedroom and 2 bedroom.  

Average where i am in North East AL is typically runs between $100 - $125 per square foot (that's based on all builder grade). 

Pros: faster time frame to accomplish plan, mother-in law casita appraises at the same price/square foot as the main house.