Gabriel Ebert, Karen Aldridge, Lesli Margherita and Lauren Ward round out the principal cast of Broadway’s “Mathila,” the closely watched Brit hit that’s opening on the Rialto in the spring.Brit thesp Ward, playing kindly schoolteacher Miss Honey, reprises her U.K. role alongside the previously announced Bertie Carvel, who brings his much-lauded perf as nasty schoolmarm Miss Trunchbull over to the States. Aldrige (“Boss”) appears as the librarian Miss Phelps, while Ebert — who gained notice in Gotham last season for his turn in widely praised Off Broadway outing “4,000 Miles” — and Margherita (“Zorro the Musical”) play the title character’s unsympathetic parents. The part of Matilda, a little girl whose special powers help her overcome a host of obstacles, has already been cast with a quartet of moppets who will share the role: Sophia Gennusa, Oona Laurence, Bailey Ryon and Milly Shapiro. Based on the 1988 novel by Roald Dahl, the U.K. incarnation of “Matilda” has amassed the kind of buzz that makes it an obvious candidate for Broadway transfer, although whether the show attracts the same heat Stateside remains to be seen. Original producer Royal Shakespeare Company teams with the Gotham-based Dodgers (“Jersey Boys”) for the U.S. version. Helmed by Matthew Warchus, “Matilda” begins previews March 4 ahead of an April 11 opening at the Shubert Theater.