Chalice of the Void was meant to be there though haha. Most of their pump spells are only 1 Mana.

Here's what I'm working with as an Esper list Esper Tokens splashing blue for Narset Transcendent and Snapcaster Mage. I still like the idea of main decking a couple Zealous Persecutions and having a Dismember and another black removal in the main in my case I'm thinking of Liliana of the Veil as my other black removal spell. I'd also consider zealous persecution in the side board to bring in for affinity, merfolk, and added removal for decks ramping with creatures. I also really like Timely Reinforcements as another sideboard option for burn and even in the main deck for that matter.

Just realized Wing Shards isn't modern playable... SADFACE.

Zealous Persecution is going to have to be my answer to mirror/Elves for now. And who knows it may be a solid answer.

I like the Esper deck, it's an interesting brew for sure. I feel like it's far more of a control deck than mine but I see where you're going with it.