Perhaps Snowing might have avoided this situation of whatever reason Regina could not call for help from Storybrooke. Either they escaped it or were captured and removed to prevent from interfering with whatever plot this is.
For this time error that was theorized, it is quite possible that these scenes like the ones from the green set and that the Emma from 7×02 might be an Emma from a different future or different time, and mate she along with some of the characters in the green set might be illusions created to trap maybe Ella2 and Lucy, and that might be one of the reasons that Henry is in Storybrooke and is trying to save his family.
So it might seem true that Snowing are in more than one scene and will help save the day. Of course, they would also still need to explain why Emma might not apart of this mission and appearing in Storybrooke cause of her one scene appearance.
Some may have theorized, which seem true, that the Zelena appearing in Storybrooke with Regina might not be our Zelena but from a different time, which could also explain why the dwarves chasing Alice and Robin did not recognize Little Robin.
This is pretty confusing of what’s going on right now. I can’t till we find out.
It is sweet to see Snowing in action one more time. The show did start out with those two, and it might make sense for the show to end (for now) and have the season end with them both.