The South Seas bring together Hawaiian melodies, early jazz and western swing, with the warm, singing sound of steel guitar at the center. Based on Bainbridge Island, the instrumental group draws from the 1920s through the ’60s, moving from “Hula Blues” and “Beyond the Reef” to “Nuages” and “Sleepwalk.” Their easygoing mix of familiar tunes and overlooked gems is equally at home with a gentle island sway or a swinging rhythm.