Pogahn Passage HM is very H+H'able. Since you have to take Margrid with you in any case, give her Broadhead Arrow if possible, Savage and Distracting Shot and a recurve bow (if silencing, even better).
After getting the diadem talk to the gate guard and give him the wrong answer. That will spawn a small mob of hostile Kournans that can be easily dispatched.
After you have freed Kormir, run to the bridge and flag H+H on the middle section. Run forward until you can see a large mob of Kournans. There are actually two different mobs and once you get close enough (past the bridge) one of the mobs will start running towards the bridge. Retreat back to where you flagged your heroes and kill the incoming mob. Release flag and go past the bridge. The second mob will attack you, try to fight it on the stairs so that your squishies are better protected from enemy fire.
Go left to the gate where you relieved a guard from duty. There are two bosses with small associated mobs. Flag your heroes and pull one at a time, then proceed to the docks. There are several Kournan guardians in two rows, they are single or in groups of two, pull and kill them as you go.
Now as you approach the dock that is marked as your objective the trickiest part is still ahead. There are two mobs on the dock, one consisting of more guardians, and the other, nasty one, has a priest and an ele boss that can cause massive damage with Meteor and Fireball. Flag your party a good way off and carefully pull the mob of guardians. If you get the whole enchilada at the same time, beat a swift retreat and retry. Anyway, once the mob of guardians is cleared, seek the ele boss and lock him as a target for Margrid. Since game AI is abysmal at observing line-of-sight, make sure that you engage the boss mob at a place where Margrid can actually hit the boss. Kill the priest, then boss, then clear up the leftovers, mission accomplished.
