The exemption applies to one property per family per year, so a second home or a rental property does not qualify the same way. If you owned more than one property during any year, the CRA requires you to choose which one gets the exemption for that year.
You still need to report the sale even when no tax is owed. Since 2016, the CRA has required every principal residence sale to be reported on Schedule 3 of your tax return, and skipping that step can result in the exemption being denied even if you would otherwise qualify.
A lawyer handling your closing through Information Services Corporation can confirm the designation history is clean, especially if you've owned more than one property or lived somewhere else for part of the ownership period. Get your hand-reviewed valuation from Joel Dyck.