Oh, that's a coincidence, I will be leaving that day, just booked my plane ticket
You should be fine with the crowds during the week. Could be a little bit of crowds on Monday as it's marathon weekend before you arrive.
It's not mentioned in this list, but also a difference people from the American parks seem to notice is the photopass. Photopass is relatively new for DLP.. It's only available for a year or so. And now it's mainly rides (among them Pirates, Big Thunder Mountain, Space Mountain, Buzz Lightyear, Tower of Terror, Rock 'n Roller Coaster) and fixed characters (not roaming). On very rare occasions you might see them in Main Street, but not very often. I think this is also a cultural thing, I don't think it will ever be popular.
If you are planning to wake up early and use the EMH, if you make sure you are at the front of the line when getting in, it's relatively easy to make pictures in front of the castle with low crowds.
With enjoying the little things to enjoy, I don't see the Aladdin walkthrough mentioned, it's not extremely special, but a nice way to use space. One of my personal favorites is also Les Pays des Contes Fees, the Storybook Boat Ride, in the back of the park. It doesn't have a CM telling jokes, but that's what I like, it's very nice and quiet and relaxing. It's my go to to get away from the crowds.
I always enjoy walking around the castle via the short cut at the back of castle stage. You have the wishing well, and most people go via the castle bridge to get to Fantasyland, this route is more quiet.
If you are into shows, don't miss Mickey and the Magician in the Studios.