The sounds are I think found in the “assets/jinryuudragonbc/sounds/DBC” folder, not sure which is the correct one, as there are a few, “ha.ogg” “hame.ogg” “hamehafire.ogg” “hamenew.ogg” “kame.ogg”. I suggest to first check how it sounds in game, and just edit the ones sounding like it. There is a start, and fire sound.
As for story mode, you need to delete your old one, which can be found in your world save folder’s “data/missions” folder as “mainDBC”.