-For Shi No Numa who ever gets the wonderwaffe just circle them up outside of the Comm Room, then whenever they way want (the person rounding them up) can go into The Comm room and hit the barrier. Then while one person is rounding them up outside, 1-3 players (if you have a 2,3,or 4 player game) stay in the Comm Room and hold it down. Leave one at the window at the end of rounds to get perks/guns. I'd suggest a Ray and an STG because the ammo flies fast so you could always just keep buying ammo for the STG plus Monkey Bombs incase the guy rounding them up outside goes down. Also, get bettys and place them all over the Comm Room, and when the Hell Hounds come go outside the Comm Room and and sit in the corner and kill them so your bettys don't go off inside the hut (this is up to you though).
-For Verruckt (this would be best with a 3-4 players) have whoever spawns in the German side (the side with MP40 and Double Tap) to open the starting debris and NOT TO OPEN ANYTHING ELSE ON THAT SIDE. Whoever is on the American side opens up the map and gets the power. (Never ever open the door next to Double Tap) Once you have the guns, have one person (or 2 depending guns/skill) get the window inside the barrier on the German side, and 2-3 get near the front of the barrier (if your are too far back they will run up the hallway past Double Tap and hit the guy at the window. Whenever needed one person can keep getting the barrier but I'd say you will have to start doing that at like Round 22ish. And of course tell the guy at the window to try to keep one at the end of a round so everyone can get perks/guns. It would also be good to buy bettys and place them at the back of the barrier incase they break out of the window (because the window gets very crowded).
-Both these strategies work very very well, but your gonna need good communication (mics) and players that are pretty decent. I hope this helped you.