Some greats in that list. Surprised you have Britney Spears as didn't think you rate her or Aguilara?
While I'm not fan of Britney, I can't deny that she was a part of the whole cropped top/hiphuggers trend of the late 90s and early 2000s. And Christina became famous around the same time and helped the bare belly trend, too, so I included her as well. I think I'll add Cameron Diaz, Mena Suvari, and Katie Holmes to that earlier list as well.
If we're doing group inductions, then we need to have girl bands like The Spice Girls, TLC, Destiny's Child, Girls Aloud, The Pussycat Dolls, and The Saturdays. And if we include modern belly bares, Kaley Cuoco, Ariel Winter, Bella Throne, Rachele Brooke Smith, Teala Dunn, and Miley Cyrus. You'll note that I left out fashion models and female athletes, because unlike actresses and singers who go bare for stylistic reasons, models and athletes are pretty much paid to wear bikinis, cropped tops, and sports bras.