Board Thread:Wiki-Related Discussion/@comment-5679696-20150815191329/@comment-1894786-20151208213914

It's not confirmed, but it is looking very likely that Dorothy is from a Magical Kansas. She's returning in the present day in her 20's or 30's to face off with Zelena in Oz, fresh from her return from Storybrooke.

As for Walsh, I would say it's looking like he's from that same world.