Have you considered purchasing shipping containers instead of building units?

You will see that Part 1 on the PCOR linked above contains possible exclusions from reassessments for certain types of transfers.

The mess would at least be contained and not have as much spill over.  

Depending on where you're located, you could make bank with that extra space, especially if it was a fully self-contained apartment with a bathroom, kitchen and separate entrance.

Whether or not the legal description conveyed did or did not contain a house is not part of their scope. 

Whitson Gordon (non BP Member)Pros: Basic is free with 60 MB of new uploads per month and sync across 2 devices Cons:Not designed for real estate Cost: $34.99 for Plus with 1 GB of new uploads per month with synch across all devices $69.99 for Premium with 10 GB of new uploads per month with synch across all devices and more featuresTrello - A Trello board is basically a web page containing lists laid out horizontally on the page so you can get a bird's eye view of your project.

Their website also contains useful information.https://andersonadvisors.com/

They also contain some flow charts for different scenarios that help to guide you on making the right decisions.

IMO, the very term ROI contains the answer:  Return On Investment.As you're in development, there is no income from the project (aka return = 0) so until there income, there is no ROI.

You store it on the job site, and pull the materials out of the container as you build.