If you can put an additinal family box in with Christening. Because there are some members of the family that are God Parents. Also Spouses of family members.
One of the Other Relationships that you can add is "Godparent". So if James Smith has godmother Sally Jones, you can go to James Smith's person page, and on the Details tab, scroll to the bottom. There you will see Other Relationships, and you can use the Add Other Relationships button to add a relationship to Sally Jones of type Godparent. And if you have sources that document the christening (including the godparents), then you can attach those sources to this Other Relationship.
As for spouses of family members, you can add a spouse to most people in Family Tree. That is done in the Family Members section of the Details tab for a person.
So everything you are asking for is already available. It's not directly connected to the Christening event for a person, but it is connected to the person and/or their relationships.