What if Quebec secedes in 1995-96?
Would the rest of Canada hold together as a federation or could seperatism spread to the West and Eastern Provinces?
I guess it depends on the nature of the separation. OTL i am not sure quebec itself knew what it wanted, but it wasn't separation at first. Certainly there were a lot of quebecois who viewed it as a method by which they could leverage constitutional modification.
Look at the question.
Do you agree that Québec should become sovereign after having made a formal offer to Canada for a new economic and political partnership within the scope of the bill respecting the future of Québec and of the agreement signed on June 12, 1995?.
If a new sort of customs union comes about with Quebec withdrawing from confederation but we have free trade and border access, hell i think they wanted to keep the money and passports, not much will change, actually the west will be happier as the centre of gravity of political power moves further west.
If it does go completely sideways and hostile, which i doubt, the Maritimes might try and join the states, maybe. I guess it depends on how much or if Quebec balkanizes and if there is violence. The Innu, who live in the northern 2/3 of quebec were across the board opposed, and Montreal was a well i think. Certainly there were some quarters in the ROC who insisted that if Quebec went they only get to go territorially with what they came in with. That could get ugly, although frankly that sort of thing is pretty unlikely.
Honestly i expect the negotiations would go on for years, and the success of the referendum might be enough for the ROC to actually revisit the constitution and give Quebec what they have said all along they want, a veto. Actually i could see Canada staying together and restructuring. somewhat. Nothing like panic to induce constitutional change.
But in answer to your question, no the rest of Canada is unlikely to break up, although we would probably move closer to the US Politically.