Option 2 requires an agreement for a coalition govt. They had the chance to do that before and couldn't (or wouldn't)If there is a Conservative minority government and there is a vote of no-confidence in Harper, the Governor General has two options:
1.) Go to another election
2.) The other parties get to decide who would form government and become PM
If option#2 applies and they can't decide then we go to another election.
The GG will not pick option#1 unless Harper was just shy of a majority and he thinks another election would guarantee a majority.
In option#2 there is no way the other parties will disagree unless their respective seat count is very close and there is a strong chance one of them could emerge with a majority in another election.
The likeliest scenario is that they oust Harper and agree that Shiny Pony would lead and form government.
Odds are Harper would prorogue govt before a non-confidence vote and call an election himself like he has in the past. Who cares how much it costs as long as he saves face in his own mind.