Hi there - for fireworks, I would say an hour. For electrical parade - you can find a spot up front along the parade route 15-20 minutes before the parade. If you want to see it at the Sunshine Plaza (front of the park), then it's a longer wait.
I've always seen the parade coming from Sunshine Plaza & going to Paradise Pier -- I was surprised to see it coming from the opposite direction a couple of Friday's ago.