Twilight Sparkle: Unicorn. A powerful wizard, (personal student of the princess), currently a librarian. Very organised, and a quick researcher, but ocassionally obsessive-compulsive and irrational when stressed, especially when things refuse to make sense (to the point that some of her custom Arkham cards on the net have her start with hysteria). Her element of harmony is Magic
Abilities: something related to magic, tomes and/or clue tokens.
Applejack: Earth pony. An apple farmer and a local rodeo champion, with lots and lots of relatives in the apple farming business. Physically strong and very stubborn. Also has rodeo-related skills (can do rope tricks and is useful against any creatures that can be herded) Her element of harmony is Honesty
Abilities: i suppose she would have the best sum of sanity/stamina. don't know about the skills.
Rarity: Unicorn. A fashion designer. a drama queen that hates dirt, but will go through a lot for her friends (this is both her strength and her weakness, as she is prone to overworking herself when she knows others depend on her. Good with high class ponies and anything fashion-related. Also physically stronger than she seems. Despite her element being Generosity, she has her episodes of greed, like physically tackling the competition when trying to catch the bouquet dueing a wedding.
Abilities: Dunno. Her magic is limited to finding gems, crafting clothes - it does make her very good at telekinetic multitasking though.
Rainbow Dash: head of the local weather team, dreaming of becoming a stunt flier. A horrible show-off. very fast, very tough (regularly crashes and rarely suffers any lasting effects) prone to acting without thinking. prone to worrying herself sick when nopony's looking. Her element of harmony is Loyalty.
Abilities: she would probably be our typical high stamina/low sanity fighter. very fast too (the "sonic rainboom" you got listed under spells is her breaking the sound barrier in flight)
Fluttershy: Pegasus and an amatour vet. As I mentioned, she is similar to your redneck druid prc. She has abysmal social skills, but mad levels of wild empathy and mad levels of intimidate (konwn as "the stare") when she is sufficiently motivated. Cripplingly shy and easily scared otherwise. Used to be a fashion model (largely against her will). Her element of harmony is Kindness.
Abilities: depending on how we represent the creatures, she might have some abilities against some. tougher than she looks, especially mentally. Perhaps some medical skills?
Pinkie Pie: an overactive pastry chef and amatour comedian/party organiser. weird and cartoonish. Gifted with a "pinkie sense" - seemingly random twitches that warn her about things, especially falling objects. Capable of pulling various weird stunts, pulling items out of nowhere, etc. Her element of harmony is Laughter. Also, she gets quite creepy when depressed - making others laugh means a ot to her :
http://www.youtube.com/watch?v=JHy3ZhY9VKsAbilities: something related to equipment, clue tokens or horror checks:
http://www.youtube.com/watch?v=NxqqD0MZKAMI have some contamination here from seeing it homebrew already. There is a limt of how much I can suggest without making you repeat what has already been done.