If you're blatantly thumbing your nose at the law, the outcome will likely be far worse than if you entered into the contract in good faith and decided to assign it (legally or not) due to unforeseen circumstances.

That way, if somehow I screwed up the numbers or something unforeseen happens I can pay off whatever amount of the mortgage I need to in order to get cash flow positive.

The price seems reasonable from my limited experience but it's an unforeseen expense.

Naming only one property can be risky as it may not close due to unforeseen circumstances suchas financing issues or failed inspections.

The question is how do I cover my self in case of unforeseen situations?

In this case the builder looks like he has a solid track record so the chances of him not performing are probably slim but you always have to protect yourself Incase unforeseen circumstances happen.

One big difference between the two is: building a multiunit is arguably a full time job - especially if it your first time; a lot of unknown variables, moving parts and unforeseen circumstances. 

If I had spent every dime on the purchase, I would have been scrambling with these unforeseen expenses.

It proved to be a lifesaver since right now everything is 100% remote.With the ongoing COVID-19 situation I need to rely completely on my property manager, local real estate agent, friends and recommendations which has helped me to get through this unforeseen rough patch.

I used the BP Rehab Estimator to come to the total BUT I think I may have been "compounding conservatism" that is to say that I overestimated how much each line item would cost, then I added in a 20% "unforeseen expenses" line item as a safety net.