Q. 1. What is a Catholic Sponsor?
A. 1. A Catholic Sponsors is synonym to the word "Godparents." There has to two "Sponsors." One is the male (the Godfather) and the other is the female (the Godmother).
When there is only one Catholic Sponsor available, you can have a "Christian Witness" as the second person. If the "Sponsor" is a female, the "Christian Witness" must be a male and vice-versa. There can only be one of each gender. One of the Sponsors has to be a Catholic.
The "Christian Witness" may be a baptized non-Catholic from another christian religion that is recognized by the Catholic Church. This person is a "Christian witness," not a "sponsor."
A "Christian Witness" with a Catholic Sponsor can never be a non-baptised person. For example, the Catholic Church does not permit Jewish or Muslim godparents to participate in the Sacrament of Baptism. This does not stop them from attending the Sacrament as visitors to the event.