Re: Is the expression "Mary and other beautiful girls" ambiguous?
As it is written, "Mary and other beautiful girls" means to me that Mary is a beautiful girl. However, the meaning can be changed by inserting a comma or two.
Thus, "Mary, and other beautiful girls" is slightly ambiguous about whether Mary is beautiful or not, whilst "Mary, and other, beautiful, girls" certainly implies that Mary is not beautiful. However, none of these three versions could be taken to mean that Mary may not be a girl, because the word "other" connects Mary with girls.
I'm not a teacher of English, but I have spoken it for (almost) all of my life....