This is neither Andrew's nor Kristen's first rodeo! Given this is both of their second marriages, they wanted to do things a little differently this time around. They have chosen to only have very limited guests for an intimate ceremony. Then their close friends and family will be invited to attend a reception celebrating their marriage.
For the ceremony itself, they want the first focus to be God- their commitment to God, God's goodness and His hand in bringing them together. Second, they want the focus to be on their commitment to each other. And finally, they want to focus on the beginning of a new family- this being why they have included their children as the only members of their wedding party.