Esper Ephemerate leans on value creatures like Baleful Strix and Mulldrifter blinked repeatedly with Ephemerate, so Extract a Confession's edict is a better answer than targeted removal. It doesn't target, so Ephemerate can't fizzle it by blinking the creature in response, and if you collect evidence the opponent has to sacrifice their greatest-power creature. Hydroblast is dead here since Esper is white/blue/black with no red spells or permanents to hit, so leave it in the sideboard despite the temptation. Cast Down struggles against their disposable creatures that just get blinked back for more value, making it a weaker removal choice than the edict effect, so the two Cast Down make room for the two Extract a Confession.