Plebania

Hi, I'm beginner and I'm trying to make mod that changes lava inside cauldron into obsidian when water floods it (similar to this video: https://youtu.be/7K7HeFbd4t8). So my question is what part of forge api should I use? I've tried to use BlockEvent.NeighborNotifyEvent event and hoped that water spread would trigger it but it doesn't seems to be the case. Any suggestions? Also i was wandering if i can overwrite lava cauldron tick method, but it seems to be bad idea.

I've just written my first minecraft mod, it makes dispensers plant saplings, till soil and plant seeds. I've done that by making new dispenser behaviors, and then registering those behaviors to certain items, ( for example: DispenserBlock.registerBehavior(Items.WOODEN_HOE, hoe); ), but I wonder if there is a way to register all hoes (including modded ones) to hoe behavior at once, or register all seeds to one behavior, etc.?