Heyzuse: Rune-Scarred Demon/Diabolic Revelation/Beseech the Queen/Increasing Ambition

Though I can't afford some of the cards here, I altered my Marchesa deck to match your choices. I'm working on tribal wizards because of this :)

I think that Apocalypse and Jokulhaups belong in your deck.

Apocalypse: With marchesa a counter on a few creatures and a sac outlet boom you clear the board and get your team back at end of turn.

Jokulhaups is even easier with all of your undying and persist and does not need a sac oulet

thematically (spoiler alert) seems like something Cerci would do

Marchesa is one of my favorite decks to pilot. Have you thought about adding Grave Betrayal for thievery fun? Treasonous Ogre is a great source of mana and also manipulates your life total to assure you'll never be on the throne.

This is such a cool take on Marchesa of the Black Rose