Having been to Coachella several times in my misspent youth, I'd say staying as far away from Indio as possible is best for anyone's overall health, even without taking unborn twins into account.
So let's speculate.
Beyoncé's husband, Jay Z, would be an interesting choice to take his wife's place. Not many people know this, but the former owner of Tidal Music is also a famous rapper in his own right. He had records and everything, before retiring with The Black Album and never releasing any music ever again. Do not tell us about the alleged music that's come out since then. We just assume that that's all by Tupac's ghost.
Rihanna is another name that's been bandied about, and that we would love to see. She has at least some of Beyoncé's stage presence. Her new album, ANTI, has major crossover appeal and has connected with the indie crowd like previous efforts connected with the frat crowd. She would also end Coachella's humiliating run of never being headlined by a Black woman.
The best troll choice would be Taylor Swift. We think Kanye might actually storm the entire festival. Hell, Kanye might form a competing festival, Kan-chella, just to tell the world how pissed he was that Taylor Swift replaced Beyoncé. For comedy's sake, we hope this happens.
If the Grammy committee was in charge, they would go with Adele. This is also a troll choice, but a perhaps more high-concept one. I don't really think of Adele as the type of act that can anchor a festival like Coachella. She doesn't have Beyoncé's dancing ability (nobody does), nor her range of songs and styles. Great singer, not a spectacular performer.
Lady Gaga is the obvious choice. She just did the Super Bowl, everyone loves her, she has a big country album, and she has never headlined at the festival. We love the idea of Gaga transitioning through her career and its distinct phases before ending on a plaintive ballad like "Million Reasons." This would be a safe choice but also one of the only ones that could hope to stand up to Beyoncé in terms of theatricality. She would be our pick, and will hopefully be Coachella's.