Maybe they want bigger lot, more land, extra lots. 

You would pay us corporate tax rate, but the retained earnings could remain in the company and not be repatriated to Canada.If you are moving to the U.S.A. and will not be keeping a presence in Canada, then once you move you should not be paying Canadian tax on your world-wide income.

How much is that extra 5k worth when it takes 3, 6 months to get it rented and then you are over budget.

As you know bedrooms are worth more to appraisers than an extra living room.

So, the landlord makes an extra $1000 per month with the same fixed costs.  

Do an assessment of value now and after you get the ADU permitted * We have been in situations where $8k for permits could mean an extra $100k in value or $2k per month in rents. 

You’d earn 0% on your $275k. 

@Hsin-I Hsu  It depends on your long term goals, risk tolerance and earning potential.A couple of bay area sayings:   Any time you can afford to buy real estate you should.  

Respect their time by giving them the information they need to include or exclude your listing quickly, and then earn their respect by answering all correspondence quickly.Making life easier for the frazzled person trying to do their job is its own reward.

Just keep in mind that condos still have HOA rules and fees, which can sometimes limit rental options or add extra costs.