In general, removal spells have become more powerful than ever in the format, so the numbers of Fatal Push declined naturally
Now heres the initial warning: if you want to support this archetype, the removal in your cube will have to get worse (or at the bare minimum slower)
Upgrade 8 Lich-Knights Conquest gives you mass recursion with all the tokens you can generate, and you can exchange your tokens for all the creatures that have previously died
By the time you have built a deck with sufficient library control to play Erratic Explosion you can start to do all sorts of wacky things with miracles and Counterbalance I also tend to find that Show and Tell is a good partner for this deck as it works with all the tutor/manipulation effects and the Emrakul
Creatures like Venser, Shaper Savant, and Hullbreaker Horror can easily serve as removal, all while providing a combat-ready body
No sleeve inside Whether it is for the Standard format (Pokmon, MTG, FOW) or Jap (Yu-Gi-Oh / Vanguard), we never put sleeves inside the holder