Is it permissible or forbidden for the school to confiscate sweets and cosmetics from female students, especially if some teachers use these confiscated items? And is this considered an embezzlement from the spoils of war (ghulul)?

If preventing female students from bringing sweets and cosmetics to school is for a legitimate Sharia-compliant interest, and the administration is authorized to do so by the competent authorities, then confiscating these items is a sub-issue of the matter of ta'zeer bil-mal (punishment by financial penalty). This is a point of disagreement among scholars, with the majority holding that it is not permissible. According to the view that it is permissible, anything of value that is confiscated must be placed in the general interests of the Muslims, and not for the benefit of some teachers.