Must one make up missed prayers if the beginning of the menstrual period was light yellowish spotting, then it stopped for two days, then yellowish discharge appeared, then one performed ghusl and the period became irregular, then the actual menstruation began two or three days after performing ghusl?

These yellowish discharges are not considered menses unless they occur during the period of menstruation.

If they are menses, then prayer is not obligatory during the time of their appearance. As for the intervening period of purity, prayer is obligatory during it, and the missed prayers during this time must be made up.

If they are not menses (e.g., if they occur outside the usual time of menstruation), then they do not prevent prayer, and the missed prayers at that time must be made up.