Rona, Disciple of Gix

• WWizards of the Coast2018-04-27
  Official Ruling
  You must follow the normal timing permissions and restrictions of the cards you cast from exile.
• WWizards of the Coast2018-04-27
  Official Ruling
  Once you begin to cast a card, losing control of Rona won't affect the spell.
• WWizards of the Coast2018-04-27
  Official Ruling
  The card you'll exile from the top of your library is determined as Rona's last ability resolves. This might not be the card that was on top of your library when you activated that ability.
• WWizards of the Coast2018-04-27
  Official Ruling
  The cards exiled from your library are exiled face up.
• WWizards of the Coast2018-04-27
  Official Ruling
  After Rona's last ability resolves, you have priority if it's your turn. You can cast the exiled card before any player can take other actions if it's legal to do so.
• WWizards of the Coast2018-04-27
  Official Ruling
  If Rona leaves the battlefield, the exiled cards will remain exiled indefinitely. If Rona enters the battlefield again, it won't be associated with the cards the "other" Rona exiled. The new Rona will exile a new set of cards with its first and last abilities. Only those cards can be cast using the new Rona's middle ability.
• WWizards of the Coast2018-04-27
  Official Ruling
  The exiled cards aren't in your hand, so you can't cycle them, discard them, or activate any of their activated abilities.
• WWizards of the Coast2018-04-27
  Official Ruling
  A card, spell, or permanent is historic if it has the legendary supertype, the artifact card type, or the Saga subtype. Having two of those qualities doesn't make an object more historic than another or provide an additional bonus—an object either is historic or it isn't.
• WWizards of the Coast2018-04-27
  Official Ruling
  You'll still pay all costs for that spell, including additional costs. You may also pay alternative costs such as that granted by Jodah, Archmage Eternal.

Rulings via Scryfall