What is the cup after the special cup in Mario Kart Wii?

Step onto the castle on the world map and then press either “b” or “a”. You can also skip the castle level entirely using a jujuem cloud.

Yes, of course. It has the same ratio, which is all that matters. You can double, half, triple, etc. any recipe, and will just end up with more or less...

No.

No. This game is single player with the exception of a Luma helper (as P2) who can make Mario jump and collect Star Bits.

The game will ask you to stand on the Wii Balance Board before actually using it, and then it will calibrate automatically.

You can unlock the special cup by doing the mushroom and flower cups, and then the star cup. It will unlock the special cup for you when you are finished.

Yes. It's the last level in the special cup. It's really difficult though, so be careful.

When you get the item, just press and hold B and you should get the item behind your kart.