a bit of a risk as you are not far down enough in france for the better weather. Think southern england in october and it is probably similar. Disney will be fab though. Just the camping could go either way.
If you are planning to stay in a mobile home (good value at that time of year) then look at the models available and check what sort of heating it has. We have stayed in mobiles with electric heating which is a lot more pleasant than gas fires.
Also, Canvas do some very nice timber lodges on that site which may be warmer.
Check if the indoor pool is open and also that the restaurant/takeaway are operating (your operator will have the details) these will be a good indicator.
We have stayed at this site a few times - it operates trips to Disneyland and also into Paris itself. These are worth considering.