You should get this setting up for the "All Warchiefs are spies" achievement. But all the advanced ones are different to tribes names.
I edited this once I figured out how to idntify them more easily.
The advanced class stats are shown under "Class Traits" on an Orc's info page.
They're:
Destroyer
Assassin
Tank
Slayer
Beserker
Tracker
Marksman
Beastmaster
Commander
Trickster (thanks to DoT Lord for reminding me)
The easiest to take down are Destroyer, Tank, Slayer and Beserker. Purely because they tend to develop the same hates and weakness'.
The hardest is Commander, especially when he is in the Cursed tribe. This is because he has damage over time and can make his minions stronger.
I can't give any deffinitive ways on taking them down as each Orc will be unique to your game. Just find worms and discover their weakness'.