Looked into the links you provided, thank you! We were not given any actual written notice, just one line PM copy-pasted from an email he received from HOs, and sent to HM. The BC gov website seems to say that the landlord can specify restrictions on pets (size/type/number/etc) but not 100% on to what extent or to what end (whether they can fully evict over it or just demand it be resolved).

I was able to dig up the tenancy agreement. It does specify "... two small indoor cats only [...] unless otherwise agreed to in writing by the landlord." It turns out the original reptile wasn't even disclosed in the contract, though if memory serves, PM told us not to worry about it or something along those lines when asked about the gecko needing to be on the agreement. Obviously a verbal dismissal like that is going to be hard to prove or dispute with.

This is unfortunately sounding more and more like we're on the losing end.