I don't have any tips on Waikiki as far as boats. I did go on a charter boat out of Maui for marlin but the boat broke down for a few minutes, the line sank, and I caught a triggerfish. Not exactly what I was after (and it was expensive).
Fished the surf at Waikiki beach and managed a variegated lizardfish and spotted flounder. Fished the so-called Fisherman's Wharf for a mess of round herring and fished the Ala Wai Canal for a Jenkin's cardinal fish, a spotted cardinal fish and a Pacific thread fin. I think all were caught on shrimp.