No.
To get toadette, you have to do all the time trials. you don't have to win them all though.
You can't.
No
I don't think that toadette is toad's sister
On Mario Kart Wii unlock all the cups and do all the time trials. You'll get Toadette. And Mario Kart DS? I have no idea why this is, but you can't get her! Good luck!
yes.
if it is the same price
Nintendo.
You don't
No, Mario Kart can only connect to other DS systems.
you cant