Have you all checked out the newest cruise option available? While it's not a Disney owned ship, they've set up charter service on the all-new river cruise ship, AmaKristina, which has been custom designed with families in mind.
https://www.adventuresbydisney.com/europe/river-cruise/
Apparently the river cruise bookings have been so popular, Disney is doubling down in 2017
https://disneyparks.disney.go.com/blog/2016/04/adventures-by-disney-doubles-river-cruising-itineraries-for-2017/
