The cast of the new musical “Tuck Everlasting,” which will have its pre-Broadway opening at Boston’s Citi Emerson Colonial Theatre in July, was announced Wednesday. Andrew Keenan-Bolger will play Jesse, Carolee Carmello will be his mother Ma Tuck, newcomer Sadie Sink is Winnie, and Michael Park will play Pa Tuck. The show, to be directed and choreographed by Tony winner Casey Nicholaw , is based on the 1975 children’s novel by Natalie Babbitt about a young girl, played by Sink, and her friendship with the Tuck family. Babbitt and Sink were among hundreds of people who gathered this week at Citi Emerson Colonial Theatre to hype the show. Also there was the show’s creative team, Tony nominee Claudia Shear , who wrote the book, set designer Walt Spangler, composer Chris Miller, lyricist Nathan Tysen, and, via video, Nicholaw.