-I feel that your motives were right, the girl definitely needed comfort, but she couldn't live under a delusion that life would be so yielding.
However, I think that the message you may have accidentally given her was that she couldn't trust anybody, and the entire world/gods were conspiring to hurt her. The course of action that I think you should have taken was to comfort her, not resurrect/murder her uncle. Another would perhaps be to resurrect Roggvir yet verbally let the little girl know that life would never again be this easy. Perhaps you could send her on a (difficult)quest to retrieve some artifact, to teach her that she must pay for such a gift. Oh. Hold on, wait, Erandur, our team priest has some information to share.
-Hey. My name is Erandur, follower of Mara. Remember that Mara teaches Compassion and love are the only real truths to a happy life. However, only true compassion counts. Such a harsh lesson seems uncalled for regarding such a small, sweet, innocent child. Mara Be with you. Now Chuckles has something to say
-Uhhhhhhhhhggggggggghhhghghrgrhaghg
-Hi. It's Casik again. Listen, all it comes down to is what kind of person you want to be. If you want to be Dragonborn, beloved hero and savior of Tamriel, you handled that badly. You should have just comforted the girl, or just given her her Uncle.
However, if you wish to be DovahKiin, harsh lord of winter and god of war, you took exactly the right path.
Morally speaking, You should have just comforted the little girl or given her her uncle no strings attached.
I Hope this was enlightening.