Personally I don’t think there’s any music that could be more fitting than Burning Homestead for all of the Force ghosts returning in one final climax to help destroy Palpatine. It’s basically the Force theme- the perfect choice!
And while the opening straight to Mustafar is cleaner and paced better, I’d stick with keeping Mustafar. I love the idea of Kylo going there and will take any version of it even if it’s messy