Is 'in whose' correctly used in the sentence? Should I say 'on' or 'about,' 'on' or 'every'?

Is 'in whose' correctly used in the sentence? Should I say 'on' or 'about,' 'on' or 'every'?

Sister Janine, a nun, gave a talk (on, about) Mary, Jesus' mother, in whose honor the feast of the Immaculate Conception is celebrated by the Catholic Church (on, every) September 8.