Actually I'm certain that you could target kari zevs expertise with reverberate, much the same way you can use mana produced by Dark Ritual to pay for an effect like extort. I don't have a rule to site, but on top of everything you could always use the second effect first, putting reverberate on the stack while expertise still has an ability left, making it a legal target.

If it comes up and there is a judge available I'll be sure to let you know the outcome, Monomanamaniac.

you should cut down Searing Blood, Wizard's Lightning and Kari Zev's Expertise to add Manamorphose Mutagenic Growth and some protection like Apostle's Blessing/ Bathe in Light/ Shelter, since you want to go full on aggro and probably dump your hand the moment you attack with Kiln Fiend adding Fling back to the deck in the post board or in the main board can give you just enough reach to kill the opponent if you couldn't in the early game. (some of the suggestions need you to splash a color)