Can you tell us a little more, Omega Force? I am not sure I understand your question. I am guessing by "first name and middle name," you're referring to the first name and middle name of a person, but it would help a great deal if you explain a little more about what you're asking and if you give us the sentence in which you wish to use this.
As we native English speakers become less xenophobic and we begin to learn more about cultures other than our Anglo one, we realize that our first-, middle- and last-name system isn't always appropriate.
"First" and "last names" can cause problems, such as among Asians, where the first name is the surname In Hispanic cultures, i.e. your own, the last name is not your primary surname.
Even among us Anglos, a person can have more than one "middle" name, e.g. former President George Herbert Walker Bush.
I have no idea what you mean by "elegant," (which often is synonymous with "pretentious,") but for accuracy and to avoid ambiguity, KB's "given names" is what I recommend as well.