From my experience, not only does species matter, but also location. For example, any of the anadromous species from the upper Fraser would have great fighting abilities since through genetics they have the ability to make it over significant distances through some treacherous water.
I believe that the July red springs on the Vedder are an upper Fraser strain (I could be wrong on this). What I do know is that they put up an absolutely incredible fight, particularly if they are on the move upriver when caught. My landed to hooked ration on these fish is about 10:1. Also, I see mention of the sockeye on the Vedder. I wonder if those are native to the system or transplanted from elsewhere - the upper Fraser perhaps?
The same could be said about the legendary Thompson River Steelhead. Incredible stamina and blistering speed.
I've hooked a few of the mammoth Steelhead on the Kispiox, and whilst they fought well, they were just that, mammoth. So they don't get my vote on a pound for pound basis.
With regard to the Squamish Chum, they do fight very hard if you get them fresh out of the ocean. In terms of numbers, this has to be the species which I've caught the most (never kept one mind you). However, on a pound for pound basis, my vote goes to the Vedder red Springs.