Five characters: Baby Luigi, Birdo, Funky Kong, Mii Outfit B, and Toadette.
I've played Mario kart for a long time and i don't think it allows you to erase time trails
No, you just have to playing with the same mii on your profile.
To unlock toadette you have to set a time on all time trails, so it depends on if you have unlocked all the cups (star, special, leaf and lighting)or not.
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!
There are 32 tracks, so there are 32 time trials.
You must get eight expert staff time trails which basically means just choose your favourite eight courses and try to beat nintendo at them.
You have to play Time Trials on all courses to unlock toadette!
to unlock any expert staff ghosts in Mario Kart Wii, you gotta beat the normal ghost in the time trials.
Birdo cannot be unlocked in Mario Kart DS. Sorry :(. She is in Mario Kart: Double Dash!! and Mario Kart Wii though. She is only unlockable in the latter. The easiest way to unlock her in Mario Kart Wii is by completing sixteen races in Time Trials.
unlock 4 expert staff ghost data in time trails mode
You have to unlock four expert staff ghosts in Time Trials.
You unlock things by winning Grand Prix and playing Time Trials.