The database on this site gives the following info:VANESSA
Invented by author Jonathan
Swift. He arrived at it by rearranging the initial syllables of the first name and surname of Esther
Vanhomrigh, his close friend. Vanessa
was later used as the name of a genus of butterfly.
If you don't think that's detail about the origin of the name, then I don't know what you have in mind.
Regarding n/t, you would find this in this site's FAQ section:http://www.behindthename.com/faq.html#abbreviation