In Spain, people commonly refer to the USA as "Estados Unidos," which translates to "United States" in English. The term "Amrica" is often used to refer to the continent as a whole rather than specifically to the United States.
The reason for two E's and two U's is because Spanish, like Latin, uses two of the initial letters when the word is plural. For example, pp for pages, plural. If it were only one United State it would be EU. Since it's plural, EEUU.
Mama jumps off the cliff with just Lilly, and upon hitting the branch, Mama and Lilly turn into a shower of butterflies. The movie ends with Victoria realizing that one of the butterflies watching over her is in fact Lilly, perhaps referencing a ghostly regret of Victoria not going with her.
It is a terrifying movie if disfigurement makes you squirmish. However, if you are prone to that, it will not be as scare (disfigurement is the main scare component). BE WARNED: this movie features some creepy and frightening disfugurement that could give a child nightmares for a while.