I think Regina volunteers to go clean up EF. She meant to die over the fail safe and she realizes how the people in the town view her. Insisting that she gets to stay in town and play happy mommy mayor after all she did would not show true remorse. By fighting to restore what she can of what she took (their land) she would be trying to right the wrongs she caused and lighten her heart in a way that might inspire forgiveness on the part of the displaced EF folk. Ogres are no joke so solving their infestation is no small thing!
As to the set pics–a dream is funny as no one person has seen all those characters in those costumes. Maybe it is the person who wrote the book?
“If I had a world of my own, everything would be nonsense. Nothing would be what it is, because everything would be what it isn't. And contrary wise, what is, it wouldn't be. And what it wouldn't be, it would. You see?” -- Lewis Carroll, Alice's Adventures in Wonderland & Through the Looking-Glass