My husband and I were a mixed faith couple at the time of our marriage. We would not have had a valid marriage in the eyes of the Catholic Church had a Roman Catholic priest or permanent deacon not been present as a witness (the actual officiant was a Protestant minister). The dispensation is to allow marriage between a Catholic and a non-Catholic:
"Without the express permission of the competent authority, marriage is prohibited between two baptized persons, one of whom was baptized in the catholic Church or received into it after baptism and has not defected from it by a formal act, the other of whom belongs to a Church or ecclesial community not in full communion with the catholic Church."Canon 1124 of the Code of Canon Law of the Catholic Church.
My understanding is that unless there is a Catholic priest or deacon present to witness in an official role, the Church takes the view that no valid marriage took place:
"
Can. 1127 ß1 The provisions of can. 1108 are to be observed in regard
to the form to be used in a mixed marriage." "Canon 1108: Only those marriages are valid which are contracted in the presence of the local Ordinary or parish priest or of the priest or deacon delegated by either of them, who, in the presence of two witnesses, assists, in accordance however with the rules set out in the following canons, and without prejudice to the exceptions mentioned in canon 144, 1112 ß1, 1116 and 1127 ß2‚3.
ß2 Only that person who, being present, asks the contracting parties to manifest their consent and in the name of the Church receives it, is understood to assist at a marriage."
So in other words, the way I understand it, if there is not a Catholic priest or deacon involved in this wedding, and assuming Autumn does not renounce her Catholic faith, Autumn would not be validly married in the eyes of the Catholic Church because of a defect in the form of the marriage (how they got married).
It is true that in mixed marriages, the Catholic spouse is expected to raise the children Catholic, and that the non-Catholic spouse is not to impede those efforts.
The fact that the Act of Settlement may tempt someone to give up their faith is just terrible.