Whenever you can, get different angles, different framing tight to wide, landscape and portrait, of the same scene/subject, work it thoroughly to give your client options. Frame a little loose for flexibility in cropping.

If some of the event is during daytime definitely get all you can then, it sounds like it might be a challenge to get good stuff after dark, but the parade itself might provide something you can work with.

If you have to use flash, try off camera with a cord or wireless, held as far away from the camera as you can reach either above or at 45 degrees or to the side and pointed back at the subject, whatever makes sense, always higher than their nose (nose shadow should always go at least slightly downward, never up).