Anna and Elsa are voiced by Kristen Bell and Idena Menzel. I knew Idena could sing from seeing her on Broadway in Wicked, but I never new Kirsten could sing. Although Idena has a fantastic voice, I would have never seen Kristen as having a voice.
Kristoff is voiced by Jonathon Groff another guy who lives on making beautiful music on Broadway. He has also been on Glee with Lea Michele. He as Kristoff works so well because you can see him within Kristoff's physique.
The written music itself is so beautiful because of the way the melodies intertwine within the underlying songs. Let it Go for me was such a great song because Idena is a very good emotional singer. You can tell how much she really enjoyed getting into the character for Elsa at this point. Also this is Elsa's turning point. This is when Elsa stops fearing herself. She becomes a more carefree person which in turn helps her later on in the movie.
Olaf's song about summer is funny because it's ironic. During the whole song he is literally singing about doing fun things in the summer. He has no idea that snow melts in the summer which just makes it more funny. The voice is Josh Gad who I thought had a gorgeous voice for someone who I've never heard of. He just does Olaf so well that I can't help but love him.
Hans also has a gorgeous voice. Basically the whole casts has gorgeous voices so I give up on trying to find anything wrong with them. If you're looking for a reason to not go to Frozen then you're are reading the wrong blog post. I feel as though I could listen to this music over and over and not get annoyed with it. The cast is so invested in making it a great musical that they really worked to create the best musical they could.
All in all I'm not going to waste more of your time trying to convince you to go see this movie. I'm just gonna say if you don't go you will be missing so much from your life. For now, Asian out!!!