If you mange to pass the game, you can start new game and choose Free Roam. At the start you get all weapons. In inventory there are 6 beehives and molotovs. Also at the start of Free Roam there are plenty od people to kill. Go to crowded place and throw molotovs to set peaople on fire then quickly change weapon to beehives. Wait till burned people die with equiped beehives.

The game is going to count that as beehives kill sińce beehives od equiped. To fasten the process throw some beehives except last one. Since it need to be always equiped, never throw last one.

As with the bees, the same is with cats. Throw some molotovs and equip cats.