I think a rideshare, or a lift offered from the harbour by someone they knew or met in Ucluelet is possible, but as I’ve said before, hitch hiking really doesn’t sound odd to me, except for the huge bags they had.
What is odd, is that there have been no reported possible sightings after they left Ucluelet if they were hitching/ridesharing.
But if they’re going via the back roads/logging roads, and ahead of the summer busy season, there may not be many witnesses to see them. Those roads would likely be pretty empty. The main roads in and out of Tofino and Ucluelet are fairly well travelled, but on some of those back roads you can go long distances without seeing any other vehicles. Maybe a logging truck once in a while, if that.