More than one. Tyranny was quite open about it. Baldur's Gate: Throne of Bhaal screws it up because it's quite obvious what's going on but it simply denies you the option of "I don't believe you."[attack] and forces you to do what they say. In Planescape: Torment the bad guy is you.
A houserule way to get around that, which we've used for ages, is that if a PC states the attack (any melee attack, not just the finisher) is non-lethal before rolling to hit, any damage done is half-temporary half-real. When the foe gets to 0 h.p. via the temporary damage (thus is probably at half real h.p. unless something else has damaged it) it is considered knocked out. Temporary damage is recovered fairly quickly, about one point every few minutes.
Except that once they formed the do gather in tribes, start fashioning Tools and clothes and weapons and customs and do breed the old fashioned way.
Not without closing the thread because of real world religion.
No need to go there. Greed is more than enough of a factor.
Matter of taste.
I'll admit it's been a minute since I read Volo, but I think that's a bit off. They aren't "tribes" as much as packs (hyenas, from which they spawn, are pack animals), the tools they use are exceptionally primitive (made of the remains of victims and stone, plus whatever they scavenge from victims), their culture is mostly about might and base urges, and that they explicitly called out that gnolls don't raise young.
