lowlight, a 1 foot pikeminnow is not a fat sucker.
Give Garry Point Park a go, it's not rare to see pikeminnows up to 2 feet around there.
Regarding bullhead, they are edible, but like you said there are better fish to eat in Canada. Lately, there seem to be more oriental anglers keeping bullhead to eat, which is ok too. It's better than seeing people tossing them onto the pier and let them die eventually (just a few days ago I confronted a boy who was not even ten I think, smoking away and kicking and stepping on a sculpin that someone else caught). To them, bullhead are probably a good fish to eat considering most fish that they eat back home are herbivorous species such as carp.
Regarding leaving the fish in the cooler to die eventually, you did the right thing to advice them not to do so. It's actually illegal to leave the fish to die if you decide to keep them. You are obligated to kill them immediately.
Still a bit too early for pink salmon, especially when there are so many nets intercepting the fish. During the first two weeks of September, we should be able to find some good fishing around here.
As for a good tide chart, I like to use
this one. Click on each day's tide information and you'll even get to see a graph of the tide height. This section is for Vancouver, so add about an hour to the Fraser around Richmond.