I would say Wind Whistler, Fizzy, Shady, and Gusty were probably the core cast in terms of showcasing and characterization. They had a good diversity of personalities types, the reserved intellectual (without the laundry list of neuroses the supposed Princess of Friendship has), the naive optimist, the well meaning worrier, and the punk with a heart of gold. They even had an episode dedicated to them. Heart Throb also featured a lot as the hopeless romantic. And sadly there was Baby Lickety-Split to serve as the child character there to annoy the adults and the audience.
The b-characters with be Paradise as the storyteller and historian, Galaxy as the wise sage, and Magic Star as the leader. The others seemed to only show up occasionally but had well defined niches. Truly was the bossy Southern Belle and Sweet Stuff was there to pretty much have bad thing happen to her for laughs like being turned into a clown.