Farming enemies post game

I 100%'d Yotei. All camps, all bounties, everything. I was looking to see if I missed achievements and I still need to Terrify 15 enemies with Onrios howl and kick someone off a cliff with Typhoon kick. The only enemies that appear are small groups of 3-5 Ronin or Raiders. Since only 2-3 get terrified when I howl I have to no-hit farm like 25-35 people and somehow lure someone to a cliff. Any advice?