Also, they have limited and low quality products that you choose from for materials such as flooring  bathtubs, and lighting, etc.

Look at new construction triplex/duplex condo sales in the heights areas, subtract carrying cost over build timeline, materials, labor and construction costs, what their desired profit in heights deals would be and that would leave you with approximate acquisition cost of the lot. 

You might try wholesaling, but even that is not going to be fast - find a wholesaler, go work for him for free for a couple months, soak all the knowledge you can meanwhile and read all the material you can get from internet, BP, Amazon books on the subject.

Take a hard look at your presentation and materials.

Then I realized the 100 hours material participation rule could be construed as active income and jeopardize my green card chance.

Have the materials failed (leaks)?

Issue a mandate to the PM that any repair over #XXX needs an Itemized Time & Materials Purchase Order to be completed by them and your signature of approval, without which the PO is denied. 

Certain materials better than others?

So, there will always be rehashing of the same material.

Lastly return and additional material you bought for a refund.