Noob questions!

[Wendigo]

Bogus & co are better handled with subtlety than with mass force, there's no reason to take unnecesarily huge losses vs the heroes.
The best tactic vs them is to leave them alone until you can bring the necessary mage power.

The heroes:
-The Dark knight has good prot & def, and likes to fly & attack rearmost.

-The warrior mage enjoys buffing Bogus with spells, and might try to paralyze pretenders & other big critters.

-Fang the troll archer can sometimes be annoying with his magic bow (some say that he can still fire at mages/commanders DomI style).

-The troll mage likes Ghost wolves, might use Orb lightning if you come near though.

-Last but not least: Bogus! with regeneration, a wraith sword, high protection & berserk he will dive through hordes of live troops, even elites.
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It might be a good idea to give your mages bodyguards to stall the Dark Knight.

Fliers with hold & attack rearmost orders work well vs the mages & the archer (hold because you do not want your fliers to run into Bogus).

Bogus is best dealt with by swarming him with hordes of lifeless troops (Raise skeletons & Raise the Dead are good spells here), that he cannot drain with his sword. He should eventually pass out to fatigue and get his huge protection pierced by the swarmers.

Alternatively, you can use MR based spells vs Bogus & the other 2 troll heroes with a pretty good chance of success, I did so recently in a MP game.