What we know so far?

Location of power switch
Using the Keys we can activate lifts (Without power)
How to create the wonder weapon and how all 4 people can gain the gun (glitch or on purpose?) We cant packapuch the gun
Easy Achievement - literally look at the dragon head before round 2
Knifing all the monkey zombie things gains a free perk at the end of the round
Building the nav card table and nav card from transit works
location of new nav card
Possible indication of PhD perk(Not confirmed)
Bowie knife and Knuckles are back!!!
New guns - An94,PDW,Svu
Need maximum players to stand in lift to activate lift.
Mule kick and Whos Who new Perks
Building the trample stream (Use: travelling across buildings, killing zombies, possible easter egg connection?)
Gold Circles with different pictures on all over the map (On top of zombie lifts, near spawn room and near the tower,etc....)
Metal balls inside dragons mouth (linked to moon easter egg)

Theories:- Stated in the solo zombies video "Mend the ridge" "if they knew they kill me"

Using the trample run, place on the gold cirlces to mend the ridge
Simply get each person to stand or go prone on one of the cirlces in a certain order (shangri la link)
Link Transit tower to Die Rise tower
Teleport to transit, new location
Use balls in dragon mouth to activate something
(PART 1)
Maxis/Richtofen speaks when you spawn(PART 1)and pick up the Svu (PART2)

If i have forget anything or you have an another hypothesis (regrading easter egg) please comment below
Part 3 remains unknown?????