I really like this Zada list! Unfortunately, Soul's Fire doesn't work how you probably think it should. Since it targets Zada and any other target it doesn't trigger Zada. You could try Heat Shimmer as another creature copy ability but this one also can copy an opponent if need be! Also, Feel free to join the Zada Discord

This is a nice Zada deck! Have you considered Reiterate or Fiery Gambit? Zada can produce a stupid amount of mana off of cards you are already running (Jeskas Will, Traitorous Greed, Mana Geyer, Ancestors Aid, Etc). You can cast Ancestors Aid targeting Zada, resolve all of the copies except for the one targeting Zada, then cast reiterate with buyback to copy the spell for infinite storm and treasures. This can be used for several other mana creators.

Fiery Gambit has won me games on the spot. If you have made an infinite number of creatures through reiterate + Twinflame or Molten Duplication (and you have already passed through combat) you can cast Fiery Gambit targeting Zada and statistically you will kill the table off of the second ability. It also works well if you need resources to try and go for the third option! If this is confusing and want a better explanation, I can help at the Zada Discord: Hedron Hideout

I like this beat down version of Zada a lot. Unfortunately Soul's Fire and Gravitic Punch dont work how you probably want it to work. Since it will target Zada and another creature or player, It doesnt trigger Zada. You could probably fill these spots with some spot removal such as Lightning Bolt or Zoyowa's Justice

Whats the win con with Glint-Horn Buccaneer?