They're gone, but I'm sure not forever. Shanghai Disney is more important, lol.
OP, you've got just about every secret and suggestion there is. I'm a Disney history nerd, and there's some hidden nuggets in WS:
1. There is a large cement lantern right as you enter the Japan Pavilion. This was a gift from the Emporer of Japan on the opening of wdw. The Emporer loved Disney and wore a Mickey Mouse watch that had been presented to him by Walt himself. I believe the lantern originally sat near the entrance to Adventureland, but was moved to its present location when Epcot opened.
2. Also concerns the Japan Pavilion. If you look carefully behind the tree line right past Mitsukoshi, you will see a large building cleverly concealed. This is a show building that was intended for a dark ride that never came to be. Over the years other rides have been proposed for the building. For now, and probably for all eternity, the building is used for storage.
3. Pause as you enter the Germany Pavilion, and take in the exterior of Biergarten restaurant. Can you guess what you're looking at? Yep, it's the entrance and exit to another dark ride that never came to be. Once you see it, you can never unsee it, and will forever lament the ride that could have been. Biergarten was an afterthought, and now fills some of the space where the ride would have been.
Concept art is out there if you look for it. Both rides would have been something.
4. Stand in the direct center of the Temple of Heaven in China (place both feet on the little circle) and speak out loud at regular speaking volume. That's the actual sound of your own voice! Not even recordings of your voice are as precise. The room is acoustically perfect. You might look a little nuts doing it, but it's neat.