At 40" there's 5 rides in Disney World that can't be ridden and 3 of those are at AK. If going on rides is the most important thing to the 4 yo, I'd go with HS. But on the other hand, AK has the Boneyard which is a ton of fun for a 4 yo. Whichever you choose, your kids will have fun.
How does it work when you have a cake delivered to your resort? Do you need to be in the room to get the cake? Can you request a time for it to be delivered? I'd prefer to not be in the room when it's delivered so it can be a surprise, but I don't know how that works.
The total overall points at a resort cannot change, but they can reallocate them. They were planning on doing a big reallocation for 2020 but pulled it at the last minute to reevaluate it. The yearly maintenance fees do increase each year but I guess it depends on what you consider to be...
I have used them twice and had great luck both times. They are easy to work with and respond fast. I actually have some points I need to rent out and have decided to list them with Dave's since I liked them so much.