To use the status textures, you need to add suffixes to your model filename or texture.
If you plan to use textures (png) you had to set generate: true.
If you plan to use models (json) you have to set generate: false, as you already have the models.
_0 - First pulling state
_1 - Second pulling state
_2 - Third pulling state
_charged - A charged crossbow with an arrow
_firework - A charged crossbow with a firework
Adding item states using suffixes
Refer to the bow tutorial, just add the missing image files.