There IS a hat that has a feather in it that is similar to what you are asking about, but, the girl's hat you are talking about is called a "picture hat", invented in about 1876, to show off a lady's face.
The boy's hat has the same slant, but is more similar to the "Three Musketeers" style.
It isn't quite a sombrero.
Look in the bazaar. They might not look like sombreros exactly, but, they're still pretty slick in style.