Questions about the Grand Prix', Challenges, Characters...

I've won the "Penguin Playground", what do I have to do to play "To the Moon or back" etc.. ?
The whole concept of Grand Prix / Challengels and unlocking is somewhat fuzzy.
You cannot see in-game what you already have unlocked, what you have not unlocked yet, what to do to unlock
a certain feature etc.
Do the different characters also have different driving properties?
If someone could answer me those questions I won't mind adding that to the wiki.....
The whole concept of Grand Prix / Challengels and unlocking is somewhat fuzzy.
You cannot see in-game what you already have unlocked, what you have not unlocked yet, what to do to unlock
a certain feature etc.
Do the different characters also have different driving properties?
If someone could answer me those questions I won't mind adding that to the wiki.....