Source: Wizards of the Coast Magic: The Gathering Video Game(s) Magic: The Gathering, Magic: The Gathering Arena Designed by Richard Garfield in 1993 as a card game, Wizard of the Coast's Magic: The Gathering franchise now also includes video games, novels and comics
No, transforming a creature doesnt remove the damage assigned to it unless the transform trigger specifies that the card is exiled then returned to the battlefield transformed
A multicolored card should take aspects of both colors and put them together or take an area of overlap between colors and enhance it
Its a bit like a self-Genesis
There are multiple cards in color with Ashiok that are going to love to use those exiled cards for various powerful effects, like Wasteland Strangler or Ulamog's Nullifier
The goal is often to outmaneuver opponents, reduce their life total, or achieve specific objectives through clever strategy and tactical play