Montreal, Easter Weekend - What's Open?
I think that all restaurants will be open on Good Friday. It is too busy a night to close doors for a restaurant....that said, maybe some will close but it will be a tiny minority.
I don't often go downtown anymore for dinner but with public transit you could go anywhere. You could take the metro, get out around Mont-Royal or Laurier station and you could have restaurants that will be more typical of Montreal than the ones you could get on St-Catherine.
Around Laurier station, you could try Les trois p'tits bouchons that is a small place that is great. You need reservations there though. On Mont-Royal street, there is Le cinquieme peche, Romeo, Misto, Le petit plateau (BYOW), Khyber pass (Afghan, BYOW that is very good and not very expensive), La Prunelle....just to name a few....