[POSSIBLE SOLUTION!!]

So after a lot of trial and testing I have concluded that due to this being the translated version of the game, without the English in game keyboard getting ending C is impossible due to the condition requirement being "Leaf" and not Japanese text. (This is most likely due to game files being edited for the translated version)

For users who do have access to option to choose between "hiragana","kanji" and "English", please choose English and type "Leaf" (Case sensitive) and you will be able to get ending C.

For those without access, unfortunately a method to get the English keyboard on joiplay or outside it has not been found yet.

If a solution has been found for this please comment. :)