Yes, Sheryl grew up in the trash heaps and back alleys of SDF Galaxy, before being adopted. She contracted the vajra infection that Ranka's mother died of, and Mao Nome and Grace suppressed it during their research on the condition. Her actual hair color is a dull gray. It's not contagious human to human, only vajra to human. Ranka's antibodies (since she was infected at conception) prevent the condition from becoming lethal. How Sheryl got it is unknown.

I'm hoping for maybe a female pilot this time, but then we'd end up in an otome version of Macross, which I wouldn't be particularly happy with. As long as we don't get another Macross 7. What I'd really want is anything with more Queadluuns. Klan and her squadron weren't enough. I know it's a series about VFs, but the second (or third depending on where you place Isamu) greatest pilot in the galaxy, Milia Fallyna Jenius, flew a Queadluun.

One thing that Macross Frontier did really well was show humans and Zentradi/Meltlandi finally integrated in society. The suspicion and racism of late SDF and Macross Plus had long ended.