There are 3 walruses, 3 sea otters, 5 harbour seals (in what used to be the beluga whale tank) and probably around 15 puffins in this section of the zoo. The Rocky Shores exhibit originally opened in 1982 with 3 walruses, 4 bottlenosed dolphins, sea lions, seals and sea birds.
Sorry but I have no knowledge in regards to the dolphins. Most of my information on the Point Defiance Zoo comes from their slim but fact-filled history book that was published a few years ago, as well as from my occasional visits.