Q1. About 2 years if the conservatives select a new leader. Otherwise, because of their strong minority position, it would not be surprising to me if this minority government went the full mandate providing Trudeau can pacify at least some western issues.
Q2. Trudeau has weathered the storm of far too many scandals and could gain a majority government in the next election should the opposition not get their act together. Despite losing seats Singh appears to be on solid ground. Scheer, a nice man, appeared to me to be out of his element while addressing such things as gay rights, abortion, and the environment. Some say the die has been cast and he cannot recover. Like him or not, as a conservative leader, I think Max Bernier would have been an effective, major thorn in the side of the Liberals. Jason Kenney, Rona Ambrose, Peter McKay, and Lisa Raitt are a few who could be viable candidates.
Q3. There are many areas where conservatives can support the Liberals. A few examples are TMX, an energy corridor, consideration of further pipelines and adjustments to equalization. With the recent CN strike, and the hardships it created, one would think even Quebec should surely change their views on pipelines.