Lysa's a bit young for marriage contracts just yet. Maybe one of the cousins....
Slight correction, if I may. A child is never too young for a marriage contract. She could be too young for the ceremony of marriage, but betrothal is another matter. Also, it was common for the "little future bride" to be shipped to the groom's family.... for insurance, especially if the groom's family was powerful.
Or the other way around, or both