You grew up in New Brunswick, you still don't know how to have a conversation in French, and you're going to learn it now? Congratulations, great, stay motivated.

Recommend joining francophone classes on any topic, sign up for an art class or a sport, that ensures that you're forced to use French. My personal impression is that francophones in Quebec will be less likely to switch to English to accommodate you than a francophone in New Brunswick would be, but that will depend upon the individual you're talking to and the situation.

There are quite a few anglophones in the Gatineau area. Some of the towns near Gatineau are historically anglophone communities (Chelsea, Cantley, etc.) so you could socialize with anglophones and francophones. But you'll obviously hear way more French.

Check out the real estate prices for the city's neighbourhoods on the realtor.ca website, "high income" can mean a lot of things in this area.