custom weapon help

i am trying to make a custom fire trident that is craftable and there are 3 things i can not figure out:
1: how can i make it set things on fire, fire aspect dose not work so i think the best option would be to set the trident on fire when it is thrown.
2: how can i increase the damage, i want it to do 12 damage but can figure out how to get it past the 9 default damage
3: how can i disable the ability to use riptide on it?