Holy shit, would you believe me if I told you I was just going to make this exact thread yesterday after finishing the land of waves arc in the anime? Damn, I feel stupid for forgetting.
But anyways, yes, Haku's story of having a hidden ice power, conceal don't feel, being treated like a monster, people can't understand those different (kid you not those exact words were taken from the Land of Waves arc verbatim), all of it makes the creators of Frozen seem like they were inspired by Haku's story.
Although to be honest Frozen was based of Hans Christen Anderson's the Snow Queen