Ah, the characters are beginning to be named!
This is Hanro, Nanuk, and Miki.
Hanro is the waterbender in
Natural Opposites. That's a quick sketch, and as you can see, I've added more detail to his clothes and face since then.
Originally, I just drew him by himself waterbending, but then I decided to add his kids. Well, there was nowhere for them to go except where I'd drawn the water, so, they're standing in a puddle.
They are from the Northern Water Tribe. Hanro is a healer, even though he is a guy. I don't have the whole story worked out for him, but it's likely he discovered the ability by accident - like Katara did - and was taught to use it by his mother or a sister or someone.
His wife - and the children's mother - was killed or kidnapped by a Fire Nation soldier (like everyone's mother) sometime when Miki was very young. They are - for some reason - living in a small Earth Kingdom town now.
Nanuk, his son, is about 10 years old. He is also a waterbender. He's very angry and distrusts firebenders because he lost his mother.
Miki is 5 years old, and is probably not a waterbender.
References:
kaioutei for Hanro's pose and the water
Shadowcross for Hanro's hands
Sellenin for Nanuk's legs
Suelix for Miki's pose