Nobody has a 'crystal ball' but the average price for a single detached home with duplex potential seems in the range of $500-600K asking price in Kitchener - isn't this unsustainable? 

There are lots out there and range from 4-7% rates depending On buy downs and a few other things but no W2 needed. 

There are SO many tech companies here, ranging for startups who would pay you peanuts plus equity all the way to Fortune 10 companies with large offices here. 

I can help get you a pretty accurate price range.

@Eddie Everette the cost is at the bottom of the page and ranges from $750-$1,000 depending on your BP membership:https://www.bpcon2021.com/ 

The price range we are looking in might be slightly outside of what lenders might consider our purchasing power just from our combined w-2 income, but the numbers easily work if ADU rental income is considered on the new property.

I have enough capital right now to pay 20% down on SFH in my area (200-220K) range.

The key of course (as you observe in the OP) is to have sufficient reserves to weather the storms. 

How do you check the credibility of the developer you partner with....will a background check be sufficient? 

I would agree that it should be something similar, but it sounds like this one is very close and should be sufficient.