Fireworks in May will be Fri, Sat, and Sun.
Disneyland is in a more residential area. Their agreement with the county is weekends/vacation periods for schools/special events, and the pollution control limits them to a specific number of settings a year. They had to go through a lot to get the extra fireworks for the Christmas time.
Fireworks in Anaheim can be heard/seen for many towns away (Fullerton, Norwalk, Downey, Garden Grove) and most residence don't view them as a positive like we do. Imagine trying to get your kids to sleep on a school night with huge booms going off at 930p....