The sea otter would require a few new animations. It's possible, but behaviourly it's very different from river otters. That said they did a half-job on the sifaka, so who knows?Sea Otter, Another Seal, Snow Goose And Hoary Marmot Could Work For Clones.
As for the rest I did mention the walrus - I know we just got two dogs but it doesn't seem likely we'd get two pinnipeds.