Ken
No prob,
I had some hits from bigger trevally, and I'm guessing they probably get about 2 pounds in there. I doubt you'll find a 10 pounder that far up, but I may be wrong. As far as type of fish, you'll have to check with someone better informed about that. I just walked out of my hotel (literally 10 feet away) and started casting
I went pretty far up, though not all the way. Fishing seemed good throughout. Look for bait breaking. The width of the canal, I dunno. I casted at least 2/3 across it. There are some mangroves I think on the other side where barracuda like to hang out. Also look right at your feet on the hotel side, I caught a few that werent more than a foot or two off the bank.
Regarding the ala wai itself, its probably ok. If it was THAT polluted, I'd doubt theyd let anyone near the thing. The major sewage spill was almost a year ago, and they are racing canoes there now, so I wouldn't overly worry. I even talked to a doctor in Honolulu and said that the chance of catching something from the water is "extremely unlikely". Take that for what its worth.
happy fishing