TL;DR - the band's dynamics are very complex, and if the storytelling elements fund I'll work with writerfolk pals to bring it to life
<takes a deep breath...>
I don't want to spoil too much, but although Ernie is the lead singer, he's not necessarily the leader of the band—or that everyone in the band is *happy* that he's the lead singer. (Though he definitely feels entitled to that status!)
Each of the band members will have their own objectives, perspectives, challenges, and paths for growing into being better people. The perspective will shift among them to tell their collective story; none will only be a foil to another character; and the band's dynamic will evolve.
Of course it'll be a challenge to develop the character and story in a way that will be "true" to each of their perspectives, complicated by the fact that (spoiler alert) some of them are physically very different in their "home" timeline (which is more or less modern-day). For example, at least one of them appears as a different gender in the future timeline (where they're the Sidecar Astronauts).
I did consider not starting the band in what might be called a 20th century "status quo" configuration, and in general portraying a more "ideal" world. But I'm interested in exploring how a deep-seated sense of entitlement can be challenged and changed; how it becomes established in the first place; and how to resolve conflicts in ways that result in all individuals involved, and society on the whole, being able to meet their potentials. (i.e. I do not believe in the Kobayashi Maru scenario!)
Yep, it's a tall order. That's a big part of why I'm assembling a diverse team of writerfolk to help me out. (The other big part is that I want to collaborate with pals whose work I admire, and who themselves have different perspectives.)