Can I change my Non O dependent visa to a student visa for my daughter and guardian visa for myself in Thailand?

You're NOT going to get any definitive answers here. AND just so you're clear, you'd only be changing the reasons for your extensions NOT getting new visas in country.

You would change your extension from "being married to a foreigner who lives here" (dependent) to being the guardian of a foreign child. It would require you showing proof of 500K baht in a bank account in your name only for 30 days before you apply for your yearly extension.

The child would change their extension reason from "being the child of a foreigner who legally works here" to one based on education using documents provided from the school.

I would imagine it's going to take the cooperation of the person you got the visa/extensions from and their company to allow you to switch the reasons for the extensions.

BUT

The ONLY place you're going to get the real answers is at the immigration office.

Go to an Imigration office and ask How