Basically for resource purposes (ideas of cave complexes left after the slaughter), I rolled up the random lairs for the area that Badaxe Jack was going to secure for his stronghold. With the exception of the first lair, I randomly generated the other five.
1. 9 Griffons-This one monster lair I placed here, because this area is where we were hunting up griffons in the old campaign.
2. 2 Gargoyles-Odd, but okay.
3. 63 Morlocks-chaotic underground cannibals, love white apes and goblins, but hate neanderthals and dwarves. Have 12 trained guard white apes.
4. 42 Neanderthals-Lawful cavemen that love white apes and dwarves, but hate morlocks and goblins. Have 16 trained guard white apes.
5. 6 White Apes-Underground gorillas (and a good excuse for dave to get more monkey figures). Known mostly for being pets to Morlocks and Neanderthals.
6. 405 Goblins-Yeah, a small city's worth of goblins. This village had 9 warbands, with 9 gangs of 5 goblins each. 16 of the gangs are mounted on dire wolves (so 80 dire wolves), plus another 15 dire wolves just guarding the village. Speaking of guarding the village, there's an 8th level goblin shaman there with 6 bugbear bodyguards, in addition to the sundry champions, sub-chiefs, chief, and a shaman with 8th level clerical abilities. This would have been one hell of a gigantic battle.
It...it almost makes sense. Morlocks and Neanderthals fighting for control of the ape breeding grounds, while the goblins try to work out what the hell to do about the gargoyles and griffons snatching stragglers on the surface.
But this brings a question to mind: Suppose there's a monster lair that's generated, and it's not one that's strictly harmful or limiting on you. Do you really need to slaughter all of them, or can you get them to work for you (by threats or promises or an alliance)? Suppose an elf securing his lair, discovered there was a band of centaurs living there. Or a dwarf found a small halfling village.
Regardless of the answers above, Badaxe Hold has plenty of dire wolf cloaks and griffon jerky to go around while it's being built.