Talented Ella, now 18, has to choose between a tacky vaudeville tour--her lucky break--and handsome, upstanding Jules in this latest expansion of the All-of-a-Kind-Family chronicles (which, in time-sequence, follows Uptown). But, deft as ever, Sydney Taylor doesn't overdo the conflict of values or leave the other offspring unemployed. Imaginative Charlotte hacks away at cousin Ruthie's bangs until she looks--says Charlotte consolingly--like "a darling little elf"; assertive, quick-thinking Henny beats out three scoffing boys for term G.O. representative (her decisive move: a cartwheel performance); and impressionable little Charlie brings home a dubious Elijah--Tony the iceman--on Passover eve. Meanwhile Ella warms to applause, knuckles under to discipline, weighs the boredom and the exhilaration, and--before the Nine Crazy Kids go on the road--bows out. "After all, there's music and there's music," singing teacher Professor Calvano reminds her--and he has a place for her in his choral group (which this spring will do Mendelssohn's Elijah). A reasonable decision, given her doubts--and a story carefully built on the realities of a warm, supportive home and a rocky show-biz career.