Now that “Lennon” has been critically thrashed after its Broadway opening, what’s next? “The producers of the critically battered jukebox musical — which, around Shubert Alley, is known as “Yoko’s Folly” — are desperately trying to keep the doors open for at least another two months. At that point, according to production sources, they will acquire the international rights to the show, which may be the only hope they have of getting back some of the $10 million they’ve sunk into the production.”