Woona is actually a full grown Luna inside a Lotus-Eater MachineKnowing that Luna would be trapped in the moon for a long time, Celestia cast a spell that would cause Luna to see her imprisonment as a fun adventure instead of maddening isolation. The Nightmare Woon is actually Luna subconsciously struggling against her own darker half.
The Three Lunar Stones are actually three of the Elements of HarmonySpecifically, they are the three stones that Luna represented before she went Nightmare Moon.
The pumpkin's name is Absolutely Nothing Else, and it insists on being addressed by name
The Bat Ponies will aid Luna by wielding the other two Lunar StonesGoing with the previously mentioned theory that they're three of the Elements of Harmony.