May I reccommend checking out my github link in my signature and looking at RegistryHelper.registerBlock(Block block, String registryName) and comparing it to yours and looking at RegistryHelper.registerBlockModel(Block block, meta)
*Edit and RegistryHelper.registerCustomItemBlockAndBlock
So if I understand correctly what you want to do is...
1. Run /AFK command
2. If the player that ran the command is AFK and receives a whisper/msg then send a reply back saying This player is AFK
Am I right?
Sending chat messages is handled server side on servers, because it is the only way for other players to the the message though you could probably have your command run the other command to possibly fix that.
Well sometimes eclipse doesn't care about something that forge cares about when outside the dev environment. Try moving the registration code to your init method.
First thing is first WHAT? Who said anything about id? And you don't need to add your mod id when registering. Search your workspace for guru. and see what comes up.
Look into ContainerFurnace and look for IContainerListener (not sure if container ia correct) that is how data is synced between server to client when dealing with guis
I have multiple ways you could do this.
1. In the constructor of the class you can add this to an array in a class then have a method that loops through all of the values in the array and register them.
2. You could pass a string into the constructor of your items class and register them there as you said.
You sre handling the inventory on the clients s8de of things it needs to be handled server side, aince you are trying to make it only client side you should use some of the default packets if there are any.