It is probably still being finalized by Game Freak. Actually, I' am glad that not every single Pokemon in Pokemon X and Y have been revealed yet. Also, when I think of a Jack-O'-Lantern type Pokemon all I can come up with is Pyro Jack from Persona 3 FES. Pyro Jack would be a cool Pokemon don't you think?
I just cant sit any other way than this. If I sit the way other people do, my reasoning ability drops by 40%.