I've got a good idea on a quad layout but have no idea where to go beyond that.  

I wish I could be of more help but I'll share what I have seen British Columbia.Similar land layout, 12 acres.4 Pads.They used a leaching bed for the grey water.They require the tiny homes to use composting toilets.This effectively removed the septic installation cost, maintenance cost and allowed them to reduce the price per pad for the tiny homes. 

Im only looking at places that have a pool/spool/spa since my intuition tells me they would do best & my family would be able to enjoy it as a vacation home in the off season (I love desert heat!)

Its a whole situation i wpuld have to lay out to you or someone that knows alot more about this business.

It seems counter intuitive to give up our 3% rate to buy another house at 8%.  

This is where the demand letter comes in, you basically lay out the case and tell them you will litigate, present your case and then offer a settlement as a solution.

Still, the system is free and is generally intuitive.

If I remove the garage space from the layout plan, the total sum of the livable space comes out to be around ~884 sq ft.

I try to start with simple guidelines that shows that you and the contractor agree in principle on the types of things that are included, then specifically lay out what I can think of.

It's simple and intuitive.