I love Surprise,her and Fizzy are my favorite G1 ponies and Surprise and Soarin are my favorite wonderbolts. Its my headcannon that she is Pinkie pie's youngest sister and takes after her Auntie Pie aka G1 Surprise.
She's not a recolor, think back, the first word pinkie pie says to twilight is "SURPRISE!" Which was the name of the pony she was supposed to be, it looked just like her, even same cutie mark but her coat is white and mane is yellow. Which is this one. Study a bit more you'll see