(Might be worth moving this into the Frostgrave sub-section)
Looking at the wandering monster table in 'Into The Breeding Pits', I reckon that the minimum number and soldier type of Gnolls required to cover them is this:-
Hyena x2
Thug x2
Infantryman x2
Man at Arms x2
Treasure Hunter x2
Knight x2
Templar x2
Barbarian x4
Chieftain x1
Shaman x1
This doesn't include archers, trackers, crossbowmen etc.which are not listed in the table.