While I don't know Canadian law, the fact of bike being in such poor shape and next to a dumpster logically says that the owner wanted to get rid of it and won't come looking for it. At the same time, since the bike was left next to a dumpster, that would make it the property of the business/apartment complex renting the dumpster. Because while no one would seemingly want 'garbage', all the contents within and/or somehow attached to the dumpster, is the property of the dumpster's renter.
Since it has been several weeks since you found the bike, I think it could be chalked up to 'finders, keepers, losers, weepers', and that no one is going to try to claim it when seeing it on Craigslist.
So from all the work you did on the bike, you could either keep it, or sell it for far more than $60.