....breaking out the damage calcs, are we? CB Adamant Eevee does 48.6% - 57.1% with QA to 0/0 Jolteon and Espeon. Eviolite Eevee does 31.4% - 38.6% with QA and barely misses the OHKO with Return.
Flareon does a clean OHKO with Facade (141.4% - 166.4%), Fire Fang most of the time (98.6% - 116.4%, clean OHKO on 0/0 Leafeon and Glaceon), though QA misses the 2HKO (40.7% - 48.6%). Superpower is a clean OHKO on 252/0 +SpD Umbreon, 2HKO from Facade if you "mispredict". Bold 252/252 Vaporeon takes a hefty 54.4% - 64.1% from Facade. This thing is a monster behind screens with nothing but a Guts boost, 2HKOing every single Pokemon in the metagame. If you happen to pass a Curse boost onto this thing...