Can a practicing Catholic marry a Protestant in that person’s church, before his or her minister? Regarding the Baptism and education of children from that marriage, may the Catholic party accept either Catholic or Protestant Baptism?
The marriage of a Catholic to a Protestant in a Protestant church and before that minister is considered a valid, sacramental marriage if the Catholic party has requested and received from the local Catholic bishop a dispensation “from canonical form” (the requirement that a Catholic marry before a Catholic priest or deacon).
In fact, in the situation that you described, a Catholic priest or deacon could be present as a witness. The person leading the service, however, would be considered the minister and would be responsible for filing the necessary paperwork with the local government office.
The couple will be encouraged to meet several times with a Catholic priest or deacon before requesting from the local bishop a dispensation from canonical form.
Regarding the Baptism and religious education of children born in a mixed marriage, the Catholic party is asked beforehand by the Catholic Church if he or she will try to raise any children as Catholics. The Protestant spouse is informed of that request but is not required to make any promise about this—as was previously the case.