my version of Reformed Cozy Glow (spoilers!)
info: Cozy Glow is the first villain to be reformed by understanding what it means to lead. one day (in her ghostly state) while she was sulking under a tree, Diamond Tiara saw her and was struck with sympathy. she went up to Cozy and told her about her similar past. then they started a conversation. soon enough, they became two peas in a pod and befriended each other. Cozy Glow realized that friendship wasn't about power or tyranny, it was about leading others in the right direction. and the instant she finally understood Friendship in leadership, she got her body back. due to the time-skip, her body accelerated to the teen years. her Cutie mark also glowed as a sign that she understood leadership.