I don't think it will hurt her either. She's been getting good reviews and one of the common complaints is she is not used enough in the film.Despite this being a a bit of a flop, I don't think it'll hurt Gaga too much. She has a new music era lined up, seems really locked in, happy and in a great head space. She also got to put her own stamp on this movie with the companion album, and has a cute smash hit with Bruno Mars which the GP are gobbling up. She'll be fine and people will move past this movie quickly. It won't plague her or put into question her movie career.
This will definitely affect Phoenix more especially with the fallout from walking away the Todd Haynes film.