The Canadian marketplace: the reality of a bilingual catalogue
Walmart Canada requires a separate seller registration and a separate set of keys from the US marketplace. What makes selling in Canada distinctive is language: it is a market where product content is expected in both English and French, and in Québec in particular that stops being a matter of preference. Planning for the second language while preparing your product records in Stokzone is easier than fixing everything in bulk later.
The connection setup asks for the same fields as the US: the key pair from the developer portal and, where needed, the partner identifier. Keys are region-specific — the fact that your US connection works says nothing about Canada.