I read a theory on here that purposed Ursa actually being Katara's mother as well. As if she fled to the Southern tribe in started a family. That could be why we've never been shown Katara's Mother's face, because it would spoil it.
- In that Swamp image, Katara's mom had dark hair, but i could see a brown tint. (but barely.)
- We never knew her name...because it would be a spoiler. But now that Hakoda is there, he may say her name...sparking some kind of plot.
- Unfortunely, the small age difference between katara and zuko doesn't help this idea.