The fastpasses are distributed only during peak at the parks during EMH, and then some are not. THey are ride-specific and not all of them are available. SOARIN' for example, distributed fast passes with ride times as late as 11:30 PM back in March!! The standby time was still two hours at that time, so I guess the fastpass was the best way to do that.
The lines during EMH are always as long as they are during the day -- we have had many discussion online here as to wether or not they are worth it or not, because the lines are NOT any shorter just because they stay open longer for the resort customers. The fact of the matter is, if all the resort visitors head to those parks that have EMH, there are MORE people there than any of the other parks on that day.