Some of these observations are personal and some are from what I read online, FWIW.
1. Pinks don't jump as much as other salmon, so if you saw jumpers in other years, are you sure they were pinks? Pinks tend to porpoise or just flip their fin or tail out of the water, especially when a big school is cruising through.
2. I think this is still pretty early for the bulk of the Fraser pink run - it is only September 1 after all, and they should be going strong into October.
3. Will they come later as the water cools? Pinks are actually more warm-water tolerant than other salmon species, so this doesn't deter them as much. They certainly aren't as sensitive as sockeye.
4. Did they stay in the ocean for another year? - No, this is one rule that Pinks follow strictly - 2 year life cycle, period.
5. Do they go to another river system? - Of all the species of pacific salmon, Pinks seem to stray the most, especially when there is something making their home waters unreachable or undesirable. This was a conclusion from a large workshop on straying salmon that was held about 20 years ago - I'll post the link if I can find it again because it is fascinating reading. The conclusion was that some strains of some species virtually never stray, while some have a stray rate of 20 percent. There was a huge variance in Chinook strains - some seemed to have much better homing skills than others.
My personal fantasy is that a large percentage of the pinks this year were eaten up by monster springs that will be returning in October! Wishful thinking I know, but I have caught and seen some really dinky pinks this year. I can easily imagine a 40 lb spring eating 1 lb pinks, but I don't know if it ever happens.