For the 1st challenge, you have to wait until each adherent has shot the obelisk before killing them. For the second set up an order for people to shoot his back at the beginning of each floor, runners first, then add clear, then stunners. For the third, just time it ig? I did this one on accident so idk For the fourth no one can have leeching or emanating when the dunks are all done if that makes sense.