No it is not, there was a version uploaded four days ago. This seems to be an issue with the author trying to access a client only class on a server, this error doesn't seem to appear in their source however.
I'm sure that if you find a bug in a mod that is either 1.7.10 or 1.6.4 and is about the age of said version you will not receive support from the mod developers. They will not go out of their way to fix the bug in that old of a version, just like how Mojang isn't going to go back on any of there changes and fix bugs for users stuck on said versions.
Yes, but it is as simple as copying over the data from the previous player instance to the new one in the PlayerCloneEvent.
I assume you mean one portal in the overworld/nether/end(whatever dimension you travel from to get to your dimension). Would I be correct in assuming that?
This means you did not register the tile entity. However if you store this in a TileEntity it will only store it once for all players. So you should store it in the player as a capability instead.
This is possible, but is not supported here and there are no tutorials. And ultimately the absolute last resort. You should just replace the entities with custom ones when they are spawned.
You can't do this.
No.
Cool.
Create a capability attach it to the player and it needs to contain at least an int for a timer. You will set the timer to the amount of ticks that you want the overlay to be rendered when the player kills an entity. And in the overlay event render it as long as the timer value is greater than 0. And in a client tick event decrement the timer variable in the client player. You may need to send a packet to the client when you detect that the player has killed an entity(not sure if it fires on both client and server).
Which isnt that hard, forge has one for block models if you need to you can take a look at that. However if it renders on a button push it requires a little more code. Assuming on button push it needs to render for all players on the player who pushed the button this will require a capability and custom packets to sync the capability. However if not you could simply have a boolean accessible from your proxies. And render off of that.
You will need a custom ItemBlock implementation which I assume you have because your block has metadata. There is where you will override the method I said above.