Just be sure you 4yo isn't going to be freaked out by the shows. It would be terrible to wait hours and then you have to leave because they are melting down.
The reason I say this is because one night we waited for Spectro back by Pecos Bill's, which the DS slept through, but just as Wishes started, he woke up and melted down. We were "stuck" to the side of the castle with him screaming...and screaming...and screaming during Wishes...as we were hearded out the front gate...waiting in line for the Monorail....on the tram...in the car back to the hotel...you get the point. Just a miserable experience for us all. I don't remember his exact age, but he was definitely under 4. This made it a very easy decision to not bother with any other late nite shows, especially Fantasmic where you have to wait long before show time.
I would think you should "test" out how they do with the MK fireworks and Illuminations before waiting all that time for Fantasmic. Let the kids make the decision.
As for the MK parades. You need to get to the curb for the 3:00 parade at least 30 minutes before...if not more. Anywhere along the route is fine. We've seen it from many different places, but in front of the castle fills up first.
As for the night time parade, I suggest you wait closer to the park entrance. That way you can skeedadle if you aren't going to stay for fireworks or you will be much closer to the exit after fireworks.
For MJJP at AK, You will be able to find a spot about 30 minutes before. We normally watch from the area by the tree & Camp Minnie & Mickey, so we can then go to the end of the parade route and watch it again as it goes past(It's my favorite parade, so it's worth it to me).