For the current wild location I have no idea, haven't played Ep18 that far in yet. EDIT: event Natu still where it used to be, Rhodorine jungle, on top of totem after you clear ur first doll encounter. Clear weather, it was morning if it matters.
I do have a box full of Natus of different natures for synchronize from Ep16-17. Trade me anything or if you somehow have 3+ 31IV Ditto I'll gladly take one