Not sure though about Social Credit - their abstention in the non-confidence vote for the Clark government is said to have made them irrelevant and Quebec turned on them. But perhaps having a non-Quebec leader of the Liberals might have helped Social Credit a bit? Or were they doomed to extinction?
The Socreds had major demographic issues and didn't have Real Caouette anymore. However, the Tories taking some Liberal votes may have postponed the inevitable and let the win a couple seats (They came within 10% in Roberval and Beauce).