Have you successfully started dating them at least, in hard mode? Or are you having trouble even starting the relationships?
Malik should be fairly straightforward after you start dating, except you also need to make sure your friendship with Mark is high. The exact requirements are 90 Malik affection and friendship, 90 fitness, and 71 Mark friendship.
Likewise, you just need to raise the appropriate stats for Nate and Jake after you start dating. They require 90 Jake affection and friendship, 90 Nate affection and friendship, 90 gamingness, and 90 confidence.