The alternative vote is not a kind of PR and the outcomes it produces are not that different from first past the post, really, so in some ways I think it would be a huge amount of effort to achieve very little if Canada had a really strong deliberative process and then simply moved to the alternative vote. It wouldn't make a great deal of difference.
Mandatory voting is a different thing entirely, but in Australia it means that voters, when they vote, have to give a preference to every candidate, because “mandatory” means not just that you vote but that you have to vote right down the ballot paper.