DLM i'm in the same progression as you are but i'm stuck on the hunter bit though :P it seems annoying and silly but i dont use jet packs on that mission it's useless to be honest.
I just start to keep prescion weapons to shoot the head and mostly i use the 3 silver skulls which helps ALOT so the knight is an difficult assasination unless you distract it with a auto sentry as i do use it alot
and hardlight shield seems useful on forerunners than convenant.
So i'm almost done mission 6 anyway on my own and i haven't finished the campaign so dont spoil the stuff on me :P