yes, it doesn't matter how you've booked your room, as long as its onsite or the Hotel L'Elysee then your room ID (which everyone gets when they check in) is what you need to access EMH (plus of course your APs/park tickets to get through the turnstiles).
the package tickets are dated. mine have always been valid for a few days after my trip but certainly not long enough to sell them and someone else to get the use of them