Just a nitpick, but Eatnemen Vuelie (the opening music) was sung by the Norwegian group Cantus...which is all FEMALE.
Info here
http://en.wikipedia.org/wiki/Cantus_(Norwegian_female_choir)
Performance of the song unrelated to Frozen.
Anyhow, the difference between a true soprano and a tenor falsetto is easy to pick out. If you want to know how, the vibrato is different, especially in large groups...the only exception would be falsetto boys choirs who can sometimes (not always) pull off a true soprano vocal range, but they also tend to have flatter tones (less vibrato)...but considering the lowest notes were easily contralto, I knew this was a woman's choir even before I looked up who sung it. I do have to hand it to their contralto section though, they are fantastic!
But, anyhow...now you know...the rest...of the story.