9 Sept 2022
If Rona is countered or dies after being cast from your graveyard, it returns to the graveyard. It may be cast this way again later.
9 Sept 2022
The casting permission granted by Rona's last ability doesn't change when you may cast it from your graveyard.
9 Sept 2022
Rona, Sheoldred's Faithful's triggered ability resolves before the spell that caused it to trigger. The ability will resolve even if that spell is countered.
9 Sept 2022
Once you begin casting a spell from your graveyard, it immediately moves to the stack. Players can't take any other actions until you've finished casting the spell.