Instead of hitting "2" and putting a fireball in your left hand, can I create a mod that would allow me to put Fireball in the left hand, and shoot it (without hitting the mouse button)?

Bonus: Can a mod be made so that hitting "3" would put Fireball in the right hand? (as opposed to hitting "3" twice, and putting it in both hands.

Bonus2: Can a mod be made that will allow additonal hotkeys? For example, useing "9", "0", "K"