Hi,
If your staying in one of the disney hotels (and have disney express) you will be asked on board how many cases you want sent to the hotel and you will be given a luggage label per case (they are colour coded to which hotel your in) you have to copy the one they have already filled in for you. usually is the surname the trip was booked in and arrival and departure date. When you hand your luggage into the disney express they will give you the bottom part of the label which you need to keep safe as you will need this when you get to the hotel to hand in for you to collect your luggage. Same happens on the way back to the eurostar. you will be given another part of the label when you hand your luggage into the hotel for it to go to the station and hand that part in to collect it. Hope that made sense.
Food wise, we have always taken our own food and drink on like sandwiches crisps fruit etc.