OWASCO — It’s become a tradition at the Merry-Go-Round Playhouse: On opening night of the fourth show of the season, the Finger Lakes Musical Theatre Festival gives its audience a glimpse at what it c. Featuring original music and lyrics by Aussie songsmith Eddie Perfect and a book by Scott Brown and Anthony King, Beetlejuice. Rupert Holmes, who’d been enjoying a career writing clever pop songs for himself and such…