Details, logistics, and FP+ priorities found HERE.
Otherwise, if you are willing to forego getting any other FPs except for only TWO OTHERS the entire day, and you really want to see MSEP with a bit less waiting, you can try for the FP+.
If you'd rather be able to book other FP+ for that day, (maybe even 4, 5, 6) you can just choose to arrive earlier and grab a spot for the MSEP parade without a FP+.
If so, I recommend seeing the second showing of MSEP at 11 pm. You can get a front row viewing spot without any wait, particularly in Frontierland and into Liberty Square.
Then you can use FP+ throughout the day and still get a good view of MSEP.
I wouldn't. One of us sits at 7 with stroller while others entertain the kids/bathroom breaks. Always get a decent to front row spot. Not worth giving up FP for entire day IMO