Expect a custom ADU to take 9–18 months, with 3–6 months for design and permitting and 6–12 months for construction, depending on complexity and contractor availability, and the speed of processing permits.

It turns out that nothing is more of a waste of time, energy, and money than this, money that could have been spent elsewhere.

My first question is do I pick a good, better, best system that costs from less to more $$ and do I justify the more expensive energy efficient system to grab a little higher rents since tenants will save money.

After months of reassemble and some customization work, the property sold for a decent profit.

I won’t try to tell you what to do other than if there’s certain properties that just consume way more energy you might consider 1031ing them into slightly larger properties where you could get better economies of scale for your time and expenses.

Do they include energy tax benefits within their study?

Many commercial leases have custom clauses. 

And a general contractor would NEVER sign a customers contract 

The PPM and Docs are customized for your project so you will need to have it outlined upfront on the structure and payout (is it pref equity, debt and the capital stack etc).

Your journey into short-term rentals sounds like an exciting shift—I can feel your energy for taking on a new challenge.