If you're fishing an estuary in North Van, Capilano is really the only one that is worthwhile. Seymour's salmon stocks are still recovering (poorly), and the mouth of the Seymour, with the lack of cover and industrial presence, is a poor staging ground for fish (this should be fixed with the Seymour estuary improvement project). I have found that the fish usually hold further out in the ocean. If you do continue going, then the usual suspects are most effective for lures - Gibbs Krocs, Buzz Bombs, Blue Fox and Colorado Spinners. As you said, the upper river will get better after some rain, as it is currently dry as a bone. Just as a note, this river is a bit hush-hush so you might not get the info you're seeking on a public forum.
But if I must ask, if you live a couple minutes from the Seymour, Capilano is not that far a drive, why not go to a river with a much better chance at hooking into some Coho?
Good luck out there!