All cards in The List retain the format legality they normally have
You can: Spend one green mana to get three mana of any one color
Those circumstances could come about when youre the only person with creatures on the battlefield, in which case youre going to want something to put Hapatras -1/-1 counters on
The fact that split cards change whether its in your hand, graveyard, or on the stack is important because of how rules consider each spell
I promise the next two precons will not take as long
Some standout cards in this deck are Anguirus, Armored Killer / Gemrazer for some enchantment and artifact removal, Godzilla, Primeval Champion / Titanoth Rex for instant-trample enabling, and Jumbo Cactuar, because power matters is fun