Bringing Disney’s classic adaptation of The Little Mermaid to the stage was a formidable task, but the resilience of songs like the wishful ballad “Part of Your World” and the acerbic “Poor Unfortunate Souls” proved undeniable. Sierra Boggess’ honeyed voice imbues the title character with dreamy longing, while Tituss Burgess’ grand performance as Sebastian the friendly crab gives a playful spark to Caribbean-influenced showstoppers like the joyous “Under the Sea” and the coaxing “Kiss the Girl.”