Well, for both of my upcoming stays I was told that there would be no Express line at all for the forseeable future. Realistically, they can't limit hotel guests unless they are going to issue a seperate Express ticket for those rides only or somehow program their scanners to be able to scan your hotel key. In addition, I spoke with someone from the VIP department, and they also informed me that there would be no Express line at all - not even for the VIP tours - until Guest Services deems that it won't overly affect the regular line.
I seriously doubt that this is true, but I really hope it is. From what I've been told, the best they can do is allow onsite guests to enter IoA an hour before they open it up to the public.