The Celtics’ season is over, unfortunately, but some of the C’s are still in town. Forward Jared Sullinger, who’s healing from back surgery, has been out and about, joining team president Rich Gotham, in-arena host Willie Maye, Boston school superintendent Carol Johnson, and former players Walter McCarty and Dana Barros at an end-of-year celebration for 1,500 middle schoolers at Northeastern’s Matthews Arena. . . . A shout-out to Devon Carney, the former Boston Ballet principal dancer and Cincinnati Ballet associate artistic director, on her new job. Carney has been chosen as the new artistic director of Kansas City Ballet.