I nominated Anytime, Anyplace for this tourney but One In A Million is my favorite Aaliyah song so this is going to be hard. That being said I don't think either of the two is overrated, though I do think Aaliyah dying so young did garner her more notoriety much like Selena who outside the Latin music community, not many knew of her until her death.
As far as Janet I can't fathom how she could ever be considered overrated. She is like the mother of female performers. I can't think of many female performers that were dancing choreography and singing like that before Janet. Aaliyah is a product of Janet in my opinion, as well as Beyonce, Ciara, and Mya. You might not rock with her songs like that but I bet the people yall choosing over her did.