How to unlock all characters

I know all characters I should unlock, so don't just leave a message, with saying the characters I should unlock only. Explain how to unlock them. Don't forget Dry Bowser, Petey Piranha, and Link.

You slowly unlock them as winning cups. That was the case for me

To unlock the half of MKPC's characters, I advise to get all trophy on GP on official MKPC track.

You can unlock the other MKPC's characters In custom track Grand Prix create by others players.
1 characters unlock = 1 gold trophy (or plus)
4 bronzes trophy = 2 silvers trophy = 1 gold trophy
2 bronzes trophy = 1 silver trophy

You can even unlock a custom character when you complete a challenge and there is a character to win. If you succeed, you get a custom character.

Yay! I unlocked dry bowser! Petey and Link left.

Someone forgot to mention that you need to win the last 5 characters through winning custom cups. Not like any of the unlockable characters are useful but still

I finally got Link, so I knew how to unlock all characters.

Unlockable by main GP:
1 GT = Koopa
3 GT = Waluigi
5 GT = Shy Guy
7 GT = Birdo
9 GT = King Boo
10 GT = Hammer Bro
11 GT = Dry Bowser
12/13 GT(I forgot) = Petey Piranha
14 GT(all) = Link

Unlockable by custom GP:
1 GT = Bowser Jr
3 GT = Rosalina
5 GT = Diddy Kong
7 GT = Dry Bones
9 GT = Funky Kong
11 GT = Toadette