I also liked villain Starlight, but my favourite is Cozy Glow, because she is an amazing villain, she is the smartest and most manipulative.She is so evil,and she is so adorable at the same time.
Pinkie Pie in a friend in deed,yes she was annoying Cranky a lot and wasn't giving him privacy,but in that episode, I realized how much she loves to make everypony smile
Well generally, the best friend would be Twilight because I think , after all the lessons she has learned she seems like the perfect friend,but the best friend for me would be Pinkie Pie !
I think when I first watched the show ky favourite was Twilight, then Applejack, then Rainbow, then Pinkie and then she was my favourite up to season 9