Going to depend on your town. I know our Development Review Board scoffed at burn/composting toilet and length of time as "primitive camp" for a neighbor who was doing basically the same thing except building an entire new structure. Their opinion was the person would likely always live in the primitive camp. The neighbor eventually gave up and sold out.

I would probably ask about phase two and see where that takes you before breaching the composting toilet/primitive camp. I would see about the renting a portolet option cause you can just say that is for the workers for construction.