The ultimate challenge for the 5 streaks is the same for everyone but technically everyone could have different ones before that.
My friend had one to get killjoys plus a 5 streak (before the ultimate), while mine were all getting double kills and playing matches.
Why 343 is giving varying difficulty levels at random to people is one of the many great mysteries of this game to me.
It's to get people to use/buy challenge swaps. I now need to get 3 kills as the ball carrier, which means I need to get into oddball first and then be able to actually get kills with a 2 hit melee while being slow. Think I am going to swap that one.