Weevil

Best answer as chosen by Asker / Ratings
2. In Glitter Gulch Mines, smash open the crate to free the UFO. Now head to WitchyWorld, climb up the pole to the pulley lift, and head to the Space Zone. Make your way over to the door and open it.

3. I think you learn the Sack Pack move in Cloud Cuckooland, in the central cavern. First, use Kazooie to hatch the egg and release the floating creature. Then use Banjo to snag the creature and float over to the area with the red glass. Then use that other pack move (the one where he puts his pack over himself) to get inside.

4. The train switch for Terrydactyland should be near Wumba's Wigwam, but I'm not sure if you need to be the grown-up T-Rex to press it down or not.
The train switch in WitchyWorld should be near the tracks. Look for a crack in the wall where you can grab onto and move across.

5. You need the Sack Pack move for the second race.

6. I know the answer is '1984', but I can't remember where all of the numbers are. The first number you get though, is in the central cavern. You need to shoot a clockwork egg near another red glass area, and have the wind-up bomb go inside. There might also be one inside the trashcan.

7. The first two should be under blocks of ice in the snow. One will need to be revived by Mumbo. In the yeti area, you have to use Kazooie to glide from one high ledge to another. Warm up the alien kid by using the hatch move.