Actually, if you book a room at the ASMu now, it decreases the liklihood that AP rates will be offered at all. If enough people book at rack rate, DC/AAA rate or any currently available discount rate, Disney will have no incentive to offer any more discounts, including AP rates. Disney only offers AP rates/code discounts if the resorts are not filling up without them.
Only a certain number of rooms are "set aside" for discounts. Having a reservation is no guarantee that you will get one of the discounted rooms. It's strictly on a first come, first served basis. There is no advantage at all to having a reservation at the resort of your choice before any discounts are announced. In fact, as mentioned above, it can be counter-productive.
Since you have a room booked now at ASMo (you have a place to stay), my advice is to just wait (as patiently as you can) to see if AP rates come out for any of the All Stars. If they do, you can make the reservation then. If not, well, you do have a discounted rate at your preferred resort.
FWIW, you do not need to buy the APs now if the only reason you are getting them is to get a discounted room (and you only need one AP to qualify for the room discount). You can buy the AP after you have booked an AP-discounted room. Of course, if APs are the best admission value for your family, it doesn't matter when you buy them, and getting a discounted room is just a nice bonus.
Good luck! Hope you get your AP discount at ASMo if that's what you really want!
