We just ate there in Nov. Our PS was at 5:35 and fireworks were at 6. We had a great view of the fireworks...the lights were dimmed and the music was played through the restaurant. Our table was one of the closest to the windows while not being right up against them. There are some tables in the back that may not have a very good view though.
As far as rushing out, that night the fireworks and park closing was at 6pm. They were still seating people as we were finishing up right before 7. So I guess they weren't rushing anyone out. It was nice to take our time and literally be the only ones walking through the castle and down Main St. Right as we came to the front of the castle the Kiss Goodnight started. We were THE ONLY ONES out there. Needless to say we were all crying.
You will have a great dinner!