The colors nearest to Key Lime, then, are Sour Apple Martini and Envy.
Envy matches a stripe in Masquerade, Quackers, Baby Quackers, Mimic, Tic-Tac-Toe, Twisty Tail.
Sour Apple Martini doesn't match any G1 ponies, so I doubt it's the correct match for just one pony. Not ruling it out, just saying it's unlikely.