He's not because Fruit Pie is simply a mind slave of that Vampire Snail. Who, by the way, is alive and well, with only his astral duplicate having suffered any harm.
I wouldn't go all that out of your way. I think the Pony/Adventure Time demographic overlap is fairly large, so I'm not sure you'll like Adventure Time. The tone of the shows is different, with Adventure Time being zany and insane while Pony is magical and sincere, but they both get most of their appeal from character interactions in their engaging world.