Do you want this thing to be the tipping point for them to leave and you have turnover costs and a vacant unit? 

I'm going to reiterate what's already been mentioned above, but I'm going to actually give you examples of why it's relevant to you to find a U.S. tax professional.1 - You're going to need to file U.S. taxes once you have property down here, there's federal filings, state filings, and sometimes local filings too2 - Tons of tax treaties between the U.S. and Canada that are easy to miss and can cost you a lot of money (important one with rentals - effectively connected income - if the professional you talk to doesn't know what this is, run away)3 - The amount of days you spend in the U.S. needs to be tracked and if you go over a threshold, all of your worldwide income could be taxable by the U.S.4 - Selling real property means up to 15% of your sales proceeds might not be available to you for years (FIRPTA)5 - Lots of nuance at the state and local levels, which both want to take as much money from you as possibleMain takeaway here is that you should find a U.S. based tax person.

What is the cost?

It's just the cost of doing business.  

I have 0 experience ground up construction loan program nationwide that does NOT require GC to sign anything, only provide proof of 3 C/O's (certificate of occupancy) over the last year I.e. built received occupancy permission now unit is on market or habitable. 700+ FICO I can get you 80%LTC loan to cost on the project on ground up construction for 1-4 units.

The land is being sold as the investment is costly with all the illegal dumping and clean-up cost.

Delapidated building not worth the cost of demolition.5.

This could easily cost you $10’s of thousands if you plan to stay in the home 5+ years when you return. 

Because of cost, duplexes are are a better choice and compete well with SFH and or apartments. 4.  

Based on my experience of running properties, even if the build were to cost you as much as $600k but you could generate $125k/year, you'd be very happy with that investment.