French Canadian here, though I’ve never lived in Montreal, so don’t count me as an expert on that city. I live in the Outaouais region, about 2 hours from Montréal. BTW, are you thinking of moving, or just landing a job with a Quebec company?
Anyway, I wouldn’t consider your description to be typical. It could be just a few people. It is true that French Canadians are family-oriented. In many ways they are similar to other Catholics (Italians, for example), especially the working class. But I think it would be a mistake to classify all French Canadians in such a way. There are class differences like everywhere else, some families are traditional, other “modern”, and so on. It’s best that you don’t make too many generalizations and deal with cultural particularities as they arise.
That said, there are a few things you should know. First, Montreal is unlike the rest of the province. It’s really a bilingual city. It would in fact be unusual for you to meet someone who did not speak some English, especially if you stick to the central and western part of the city. In business, everyone speaks English. You can try to speak French if you wish, but if time and clarity is an issue just speak English.
Secondly, do not enter the language debate. Very sensitive area. Be aware of language laws, but avoid conversations about them. For the record, there are three basic “language laws”: 1) Public signs must be French or bilingual - if the latter then French must be more visible; 2) The official language of the workplace is French (with the exception of very small businesses); 3) Immigrants must send their children to French schools. Of course the official language of the province is French only, however the government offers services in English - it just doesn’t advertise that it does.
Avoid the nationality debate as well. It’s not a hot issue right now, but just in case. French Canadians are basically divided equally between federalists and nationalists. Do not assume they are either, athough businessmen are generally federalists. Nationalists will sometimes correct you if you refer to them as French Canadians rather than “Quebeckers” (Québécois); conversely some federalists (and French Canadians living outside of Québec) might not like being called a “Québécois” because of the nationalist flavour of the word.
Those are the main pitfalls, or potential faux pas. Hope this helps.