Well first you need to Subscribe to an event called LivingSpawnEvent here is a good tutorial on EventHandlers. You'll want to take the entity given by the event parameter and scroll through the tasks field and change the AI to it's corresponding alternative.
Well I'm sorry I was only aware of
public IIcon getIcon(int side, int meta);
// Not
public IIcon getIcon(IBlockAccess world, int x, int y, int z, int side);
Well now that I see that I know what is possible should really look more into stuff before posting.
Because that is the way java works. If forge supported it you would be able to modify the forge source directly leading to incompatibility between mods. You can change the AI of mobs in the way I suggested here
http://www.minecraftforge.net/forum/index.php/topic,40955.0.html
Forge doesn't support modifing base classes. Plus the way you did it wouldn't work anyway. To do so you would need to decompile minecraft code edit it and then recompile it and use that as your jar file to launch minecraft, which wouldn't be compatible, what is it that you are trying to change?
Minecraft has these things in 1.7 called IIcons. They are variables that store the textures information. getItcon will help you determine what IIcon to use per side although I don't see any way to make that depend on the surrounding blocks.
I would use
// To do get the instance if the container that the player has open
player.openContainer
// Grab which block the player is looking at using MovingObjectPosition and the players look vectors.
Chunk chunk = new Chunk(world, 0, 0);
if(!chunk.isLoaded()) chunk.setChunkLoaded(true);
Something like this, but you should use
world.getChunkFromBlockCoords()
// or
world.getChunkFromChunkCoords()
No I have not used this Animation before, but I'm pretty sure that some people like LexManos and Diesieben know what it is.
What, who mentioned grammar.js and an engine.json?
I'm not sure if this will work or not, but you could subscribe to LivingUpdateEvent and check if the entities aia is disabled and if it is run the update anyway. Though if it does work it may cause lag as all entities will be receiving AI updates every tick.
Well it seems that it doesn't matter if you use your MODID or the instance forge works both ways after a little digging into that. Sorry for bothering you, I've just never seen it done that way until now.