Have you considered Buyback as a way to get things back out of the grave on resolving the Kess cast? These aren't great cards, but maybe worth thinking about at least.

Corpse Dance might work well since you have so few creatures to interfere with retrieving a Dualcaster Mage or the like.

Demonic Collusion as a possible swap for Increasing Ambition. It's a higher cost to tutor two cards, but lets you toss some stuff in the grave and you can repeat the combo on later turns or if you recast/flicker Kess.

Maybe Reiterate for See Double?

KongMing I like where your head is at with your comment. The reason I play See Double over something like Fork or Reiterate is the upside of a modal spell. The amount of times see double is an instant speed clone, more than once coping something silly like a Solemn Simulacrum, has actually been relevant. The longer I've played this deck the more I've messed with ways to reuse spells without relying on kess being in play, and buyback did cross my mind before. Used to run Walk the Aeons in an early build with turn spells, back when "kess beats" was plan B. I don't see myself running corpse dance, as really the only creature I care about once it's in the grave is Rona, Sheoldred's Faithful and I can just discard cards as an additional cost to recur it. As for collusion, I very rarely spend 5 Mana to tutor from hand, increasing usually gets discarded to Faithless Looting, Careful Study or something else. Ambition is in the deck because if I cast it with kess, it only cares it was cast from the grave- not that I spent 8 Mana.