Just a thought on the Disney thing.
A much shorter (and sell her on the much more authentic french experience) is Jardin d'Acclimatation, right in Paris. And in a nice park to boot.
https://www.jardindacclimatation.fr/en

Alternatively, while it takes about the same time, much cheaper is Parc Asterix.
https://www.parcasterix.fr/en

For Belgium, unless you really want to spend late nights in Antwerp or Brussels, I would just pick one and train to the other. Easy train rides.