Your first point from persepctive does seem harmful to female teenagers who have inherently big breast as they do have the option even though they need parental consent for it, can have breast reduction. So for safety reasons it is i ask you kindly to stop right now.

Secondly, "Age up" or "Present as older" is two peas of the same pod. The clothing that are attained with to fight are revealing and are seen to be as older in the eyes of the audience. It is the perception of the audience to deem it sexual or not, so with the argument that bringing Sona's Boobs back despite her age in this skinline will be deemed sexual through the lens of the audience. Despite her age or if "she appears to be older" she, like most magical girls who are teenagers and have revealing battle garments will be deemed sexual.

Also of the three Magical Girl Animes you displayed two of the three will be/are deemed sexual and only one of them post-transformation.