Can school administrators sign parental consent forms for research participation of minor students in loco parentis?

TL;DR: Can school administrators sign parental consent forms for research participation of minor students in lieu of parents?

Hi all, I need your help developing arguments for this:

I am a educational researcher who usually conducts my research on college students (self-report, minimal risk studies on achievement motivation). I am planning to conduct some research on minors (secondary students) on the same topic using the same methods (e.g. self-report questionnaire). To uphold ethical standards of research, I obtain informed consent (using an informed consent form) from college students who are in the age of majority. But for pupils who are still minors, I would need to obtain both parental consent and student assent.

There is an argument that the Family Code (specifically Articles 218 and 219) allows for administrators to sign off on the consent form in lieu of parents because "Authority and responsibility shall apply to all authorized activities whether inside or outside the premises of the school, entity or institution (218)" and if the school administration authorizes data collection, then technically, the school administrators can sign the consent form.

I'm not really convinced, so I'm looking to this community for insights. I'm NAL so I would appreciate legal documents (perhaps a DepEd circular, precedent case, etc.) that could help me widen my understanding of this concern. I have read through the Philippine Health Research Ethics Review Board's (PHREB) 2022 National Ethical Guidelines for Research Involving Human Participants but it does seem to be discussed there.

Thanks for the insights!