So there is a major project underway to improve the transit system but it will have huge effects on the transit already in place.
rem.info/en/news/transitional-network-deux-montagnes-and-mascouche-lines-starting-january-2020
It will in particular effect the train lines Deux Montagne and Mascouche. So if I were you I'd try living elsewhere. As knit said above, Dorval, Lachine, Lasalle are all part of the West Island, along with Beaconsfield, Point Claire etc. Very anglophone.
I guess your DH is working downtown? And you have a dog, so if I were you I'd be living downtown, near to Parc Mont Royal ( Montréal's Central Park if you like!). Its a huge beautiful park, loads of trails, bike paths etc, little lake, cafe etc.
You can definitely find work without French - it massively depends on your field though, and where you want to work, not just in which company but the location too I. E in the West Island they will not insist on French that much.
W/r to heating homes - all homes are WAY better insulated than in the UK. Think good double glazing, amazing central heating etc. I've never seen a drafty house in Montréal, it's not like the UK at all for that. Electricity is cheap because its all hydro sourced electricity, so you will not see huge heating bills. You have to keep heating on all the time though, none of this switching it off overnight as the pipes will freeze.
The weather is extreme but you adapt and get used to it, you really do. It's never humid and damp like in the UK, is a dry cold. There is nothing better than a cold say, fresh snowfall and lots of sunshine!