I didn’t know till recently that there used to be entirely separate brand names (not just model names!) for some American cars sold in Canada. For instance, Mercurys in the 1950s were known there as Monarchs.
In checking Wiki, it wasn’t the VTEC, but I don’t see any mention of an engine partnership between them, either. However, I did read something about the two of them developing an engine together.
Not just Canada, but Europe as well. GM owns Vauxhall in England and Opel in Germany. Both companies have their own unique models, but also sell rebranded GM cars. Ford, IIRC, does something similar in England and Germany. (Merkur is the German word for Mercury.)
And I just barely remember Vauxhalls being sold in Canada.
Platform =! chassis
When car makers say that two cars share the same platform all it means is basically that they have the same mounting points for engine, suspension, etc. so the same mechanical parts can be used.
But the chassis can be entirely different. One car could be a big honking 7-seater SUV and the other a low two seater sports car.
To take this digression further OT, GM is now selling Chevrolet models in England. They’re marketed separately from Vauxhalls. Wait! Here’s how I can bring this post back on topic: the Chevy’s here appear to be badge-engineered Korean models, like the Aveo.