Players later in the turn order will know if players before them are discarding, but they don't get to see what those players will discard to help them decide whether to discard themselves
As an example, Nightveil Specter would give you three devotion to blue and three devotion to black, though for the purposes of Phenax, God of Deception, this would only count for three total devotion
You get an emblem with "You may cast spells from your hand without paying their mana costs." Legendary Planeswalker - Tamiyo Tasha, the Witch Queen Whenever you cast a spell you don't own, create a 3/3 black Demon creature token
The AI bots must be able to make judgments based on the games mechanics and rules, knowing which moves to make while playing against an opponent
The only true tribal deck that I've personally seen work in cube is splicers