o far, I've scraped together that...
Animals do not count as kills - even guard dogs
If a vulture eats a tranquilized enemy - It counts as a kill. However, it's only in one section and takes a while for it to occur
Even killing bosses counts as kills - They must be Tranquilized
throwing poisonous animals at the enemy could kill them and count
CQC is fine as long as either Zzz appears over their head or floating stars. Using the Knife or chocking too long could lead to a kill
Don't use any explosives in the game, it could lead to deaths without even noticing
Tranquilizing enemies on the motorcycles do not count as kills
Bees do not kill guards
Bearer... Seek.. Seek..Lest..