Apply for a dimensional variance on the vacant lot to allow a smaller lot and/or setback so it can be built upon.Your best first steps are to sketch a plan, possibly with an engineer's help, then contact the zoning department to discuss your idea with them to get informal feedback on your liklihood of success before you spend a lot of money.

I know you mentioned doing STR, but then you need to spend another $10k+ to get it furnished.

This could be just specific to the real estate industry, but in both recruiting and cybersecurity consultants (hackers for hire), the ones that start their own business/consultancy, are the ones who after spending 2 years (usually exactly 2 years which is when recruiters will message them), the high performer will either 1.

Canadians just spend too much time at home

In Miami, we all know how people use rented cars, boats and houses to give themselves credibility.  5k for me is pocket change but I never like to spend money on a losing investment. 

Also, what if you spend thousands of dollars on a brand-new DADU, only to have the seller reaqcuire the house?

IMO how you treat the BRRRR project regarding who you hire and what you spend and timeline depends on the region and SOW3.

Don't forget to include how you are going to force those without insurance, or who don't want to spend the insurance money, on clean up.Then there's the question of refusing to spend tax dollars on protecting houses impossible to protect, but that's for another day.

I wouldn't spend one minute worrying about that violence. 

My core investing philosophy is pretty simple, and has done very well across almost two decades and numerous cities:1) Invest in cities with population (and job) growth2) Invest in parts of the city where household income is near the median (or slightly below)3) Invest in properties that provide cash flow from day 1 Thank you for sharing that.