Depends a bit on which Disney hotel you are staying at. We were staying at the Contemporary during our last visit and for the nightly fireworks, there is an outdoor area with seating at the far end of the 4th floor (same floor as Chef Mickey's but opposite side of the floor). Great place to sit and watch the fireworks and you can also avoid the crowds/lines exiting MK once it is over.
My impression from watching various parades is that regardless of where you stand/sit there is always the chance others will try to squeeze in front of you to get a better view. I can recall watching one of the MK parades from that elevated train station near the front entrance a number of years ago. Not sure if still there or what sort of seating might be available. Being on the 2nd floor made parade viewing easier.