Birdman or The Unexpected Virtue Of Ignorance (2014) echoes a similar structure with a mysterious superhero alter ego levitating about in his head is funnier and seems a fitting alter ego for Michael Keaton's Batman fame. Edward Norton is brought in to save the play when another actor departs, but he proves to be difficult on set and full of himself while also making him kind of fun and funny. Emma Stone, the daughter that gets no daddy time, is recently out of rehab and crackles with a wisdom that eventually even her dad notices. Sparks surprisingly fly between Norton and Stone as he seeks her attention.
I'm not sure if Birdman is channeling Opening Night, but for me the similar territory of opening on Broadway pulls them together, with Birdman being a bit more quirky and fun.