Alright, alright, sorry I didn't reply my solution...I suppose that's a tad selfish, but I figured out the method to this madness of a mission.
PIKEMEN. I brought as many Pikemen units as I could and some archers for good will. Pikemen and archers the best against Ogres, but you need to move quick.
The mission is as such:
Start > Ambush > walk > Ambush > walk > Ambush > end mission.
So you just need to be ready three times. Once you're done killing the Ogres immediately head to the next ambush spot and get working. Be faster than the NPC but don't tread too far ahead as you want to make sure he has the majority of backup when/if the fights. He generally goes straight or to the right.