Changing 2.0 character abilities

[The Dwarven Digger]

I'm making an episode that will use Uncle Broadsword (With custom graphics), and his fire ability seems to be no different from his normal state. So, I wanted to add two fireballs that shoot out when he uses his ground pound ability, like when you stomp an enemy with the red boot. However, I am not sure how I would do this, whether some extra memory values or another variable is used for the ground pound and whether I could use these to activate it. I would also like him to shoot a fireball on the second sword swipe, similar to his hammer ability.

(Also, may or may not be related to LunaLua, but I would like to know if I can make custom graphics for the npcs that are changed, as currently Uncle Broadsword's graphics overwrite any custom ones. This is mainly for the SMB3 Star, as I have workarounds for the others)