Note: Supercharge will only be wasted since the Boss aura prevents more than 35% of max health from being taken in a single hit. If your Cogblade Raptor is swapped in over your Runeforged Servitor, Screech will work to win the fight since your raptor is faster and will beat out the heal.
Not sure if it matters, but all my pets were SS, only ran it twice, once while writing the script and doing the fight for the achievement and again to test the script and Snozz died on the last headbutt both times.
Used Foe reaper instead of Cog Blade. Started with Boar (1,2,2): PASS.
Reaper (2/2/x) comes in: Wood chipper first. Overtune 2nd. Wood chipper again. Lil bling (2/x/1) comes in. Make it rain. Then inflation. Boar comes in. Headbutt first. Then Pig out. Then use charge for last hit.