There was a tour during the 50th celebration that included seats for the fireworks or parade depending on what time you took it. That tour is no longer offered. The walk in walts tour does not include seating for any of the shows, parades or fireworks. The only "tour" that currently offers it is VIP services. Its a minimum of 4 hours, $75 per hour if booked in advanced. More if booked at the last minute. It does not include priority enterance to any rides. But, it does include seats for any fireworks, shows, parades, etc that you might need.
edit: seating for parads and fireworks do not need to fall in the tour time. Say you have a tour from 10am to 2pm. Then you could see the parades and fireworks later that day. They can also include DCA in the tour and those shows/prarades as well.