Chris Willman Senior Music Writer and Chief Music Critic Introducing the Manhattan Transfer’s final show at Walt Disney Concert Hall, writer Bruce Vilanch emphasized the multi-genre status the vocal ensemble built up and maintained over a 50-year-plus career that, from all indications, really was coming to a close Friday night. “I’m thrilled to be here for the final concert of the greatest pop-rock-jazz-soul-R&B-scat-vocalese-Brazilian group in the history of America,” Vilanch said. In keeping with that multi-hyphenate spirit, the group’s apparent swan song in downtown Los Angeles’ toniest venue was a happy-sad-ebullient-misty-eyed affair.