Janet Jackson should be in the Trinity, she was one of the biggest and most influential female artists of that era. When every male and female performer to come afterwards (Britney Beyonce, JY, Usher etc.) are citing you as an influence then you've left a massive impact.
Also Rhythm Nation was the #1 selling album if 1990 in the US, Janet. was in the top 5/10 selling albums in both 93/94. The album was global, That's The Way Love Goes was global. The iconic RS cover. Her image and sex appeal
Mariah, Janet and Celine are the Trinity but Celine didn't really leave too much impact.