The highest prayer is that all will eventually come to know Christ! We already know this, but we just don't know how each will receive Christ. Praying that people become specifically Orthodox in this life presumes that they want to and that people are in charge of destiny, yet only God truly converts. You can only try to help people see Christ, but you can't take it upon yourself to convert them or expect that they will convert. That being said, I am not saying you should not seek the intercession of saints.