I'd give the prospective tenant a choice, 1. one month longer than projected completion and they must vacate on that date because you will be finding a new tenant 30 days before they leave or 2. two month's extra and if there are delays for any reason you will allow them to remain until the house has a certificate of occupancy. 

Current financing available, construction costs and how to reduce them, appraisal trends, best practices when building on investment properties, rental values, design trends, how to minimize the construction time, ideal target markets, which city's DOB's are helpful and which aren't, preferred vendors, etc.

You will end up with a major delay.

Another way the additional cost is sometimes mitigated is that contractors and suppliers are paid more reliably and therefore the process sometimes goes smoother and there are perhaps less change orders or delays - both of which are costly.  

Some background on this: This follows the tiny house/minimalism live style.

I just picked up a (2%+) deal last week that needs minimal rehab.

I didn't have the cash so I used future value appraisals and sweat equity to minimize my cash needed for each deal.

Its main purpose would be to prevent (and minimize) potential conflicts as much as possible.

that is the first step in allowing you to start claiming that there’s financial hardship in the delays.

Also don't want to lose potential renters if work gets delayed, etc.