So let's see…
Twilight is the independent, competitive evil genius who wants to take over the world and wants to learn magic for useful things.
Rainbow is like a Peter Pan but with a more explosive personality, goes around the world visiting different aerial teams to get more skills. Eventually she forms her own squadron and still has enough time.
Applejack goes on adventures, including sailing, spaghetti westerns, kicking wizards in the face, saving ponies, and often transforms into a dragon, skeleton, etc.
Fluttershy is basically Fluttershy+Applejack, but more intelligent and laidback while still delivering a buck, and she lives on the farm. I guess she relieves Applejack of her farm duties and tells her to go see the world like a free man.
Pinkie Pie often controls her own business; circus ringmaster, flying balloon ship, sweets factory, stuff like that.
Rarity gets ice powers along with her craftsmanship, and lives in some castle and has her own crystal mine. I guess she's already a duke or a princess?