I've done several play throughs of the new origin zombies map and I'm slowly getting to grips with it. In this post ill also mention what the challenge box does and the generators.
Generators: simple enough, the player(s) need to pay 200 per player in the game to activate one of the six generators throughout the map. When a generator is activated there is a small timer. During this time you need to stay on the platform and kill the crusader light ing people. Once the timer is over the crusaders die and power is supplied to facilities in the area.
The Challenge Box: The challenge board and box are found in the starting room with a small leaderboard. Here you see 4 challenges;
1) 115 headshots
2) power up all 6 generators ( note that the player has to be there for every generator that is powered up.
3) spend 30000 points
4) full the four chests ( zombies need to be killed next to the chest, their soul is absorbed and eventually the chest fills.)
Upon doing ONE of these challenges the player can open the challenge box recieving a reward ranging from a pack-a-punched weapon to an extra perk and even a new knife animation.
The actual Easter egg: The Easter egg starts at the pack-a-punch machine. In the area beneath the machine there's a small room. The player needs to pick up a grammaphone which is usually found nearby and a music disk ( under the heading music parts on the back menu) these items in combination open up a large underground chamber where Staves are built.
There are four staves with a corresponding element. To build a staff the player needs a colour corresponding music disc and three staff specific parts. For example a red music disc will allow you to unlock the fire staff and the parts can be found in several different ways like:
Killing a panzer big daddy robot thing that randomly spawns
Shooting down the yellow plane in the sky
The mystery box
Scattered around the map
Two parts are only accessible via the tank. When the tank is doing its set path there are places you can jump to
Once the player has three staff parts and the corresponding music disc the player needs to follow the signs to a crazy place - there are four and each one is elect specific
By generator six (ice)
Near generator one and the start room (fire)
Near generator five (shock/lightning)
Near generator 4 and juggernog ( wind )
When at the crazy place you need to place the grammar phone on the table and rocks should rise from the ground and a portal is formed - enter the portal and you are in a crazy place. There's no other way to describe it. Run to the pedestal with the element your looking for and grab the element and then return to the pad you entered on and you can teleport out, and build your staff underneath the pack-a-punch.
This is as far as I've got but there are some things I've noticed and I have an idea what you need for the full Easter egg.
All four staves complete is an obvious requirement of a trey arch Easter egg
Also below the pack-a-punch room is a handful of levers which spin 4 floating circles. Maybe you have to hit them with a specific staff? Maybe it's a pattern you need to form?
If I find anything else ill add it in, but I hope this helps.
Goodluck completing the Easter Egg.