Sorry, I should have made that clearer. I meant for you to ring Eurostar (I've amended my other post), it's definitely worth seeing what their prices are as even with 20% off with Disney you may still be able to get it cheaper independently. Even if you arrange your travel with Disney I think it's only your park tickets that you'll be given on the train, I'm 99% sure your room number won't be allocated until you check-in at your hotel which is when you will arrange your breakfast time. You can also purchase Express luggage service even when you've arranged your travel independently, you just phone up Disney and get them to add it onto your package.