Definite progress is being made in the theater these days when an out gay actor like Isaac Powell can star as Tony in the Broadway revival of “West Side Story,” while way downtown, at Abrons Arts Center, out and proud lesbian performer Beth Malone, a memorable Tony nominee as dyke cartoonist Alison Bechdel in “Fun Home,” is also playing a traditional “straight” musical role, doing “The Unsinkable Molly Brown,” directed by Kathleen Marshall.