Marriage prep class requirements appear nowhere in Canon Law. It is simply parish or diocesean red tape. …
The prep is canon 1125.3.
I expect it will be a
convalidation with dispensation for lack of form and dispensation for disparity of cult. The valid marriage only begins with the consent given in the convalidation. Catholic matrimonial consent is different than Baptist.
Latin Church canons 1983:
Canon 1160 For a marriage which is invalid because of defect of form to become valid, it must be contracted anew in the canonical form, without prejudice to the provisions of Canon 1127.3 [4].
Canon 1124 Without the express permission of the competent authority, marriage is prohibited between two baptised persons, one of whom was baptised 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 1125 The local Ordinary can grant this permission if there is a just and reasonable cause. He is not to grant it unless the following conditions are fulfilled:
Canon 1125.1 the catholic party is to declare that he or she is prepared to remove dangers of defecting from the faith, and is to make a sincere promise to do all in his or her power in order that all the children be baptised and brought up in the catholic Church;
Canon 1125.2 the other party is to be informed in good time of these promises to be made by the catholic party, so that it is certain that he or she is truly aware of the promise and of the obligation of the catholic party.
Canon 1125.3 both parties are to be instructed about the purposes and essential properties of marriage, which are not to be excluded by either contractant.
Canon 1126 It is for the Episcopal Conference to prescribe the manner in which these declarations and promises, which are always required, are to be made, and to determine how they are to be established in the external forum, and how the non-catholic party is to be informed of them.
Canon 1127.1 The provisions of canon 1108 are to be observed in regard to the form to be used in a mixed marriage. If, however, the catholic party contracts marriage with a non-catholic party of oriental rite, the canonical form of celebration is to be observed for lawfulness only; for validity, however, the intervention of a sacred minister is required, while observing the other requirements of law.
Canon 1108.1 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 cann. 144, 1112.1, 1116 and 1127.2-3.
Canon 1108.2 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.
Canon 1127.2 If there are grave difficulties in the way of observing the canonical form, the local Ordinary of the catholic party has the right to dispense from it in individual cases, having however consulted the Ordinary of the place of the celebration of the marriage; for validity, however, some public form of celebration is required. It is for the Episcopal Conference to establish norms whereby this dispensation may be granted in a uniform manner.
Canon 1127.3 It is forbidden to have, either before or after the canonical celebration in accordance with 1127.1, another religious celebration of the same marriage for the purpose of giving or renewing matrimonial consent. Likewise, there is not to be a religious celebration in which the catholic assistant and a non-catholic minister, each performing his own rite, ask for the consent of the parties.