to answer your questions. There is a bunker behind the park where the main pyro behind the castle comes from. Then there are locations along the railroad tracks for the 180 degree fireworks they use for special event parties. THen there are 5 Pyro bunkers per side with (exploding shells and non exploding shells) on the fantasyland roofs.
The non exploding shells you are referring to are called comets. Its the same shell used in Illuminations for the opening shot. This was chosen because its continuous burning and never explodes, thus being able to be shot over guests heads.
Here are 3 pics.
http://www.flickr.com/photo_zoom.gne...1628596&size=o
http://www.flickr.com/photo_zoom.gne...0766613&size=o
http://www.flickr.com/photo_zoom.gne...0790005&size=l