In the Original full bodied design approved by Zero-G, Avanna was actually an elf and sported a pair of short pointed ears. These were later discarded from the Yamaha re-edit.
The elf ears were kept on one of the faded pictures that appear in the background image of her boxart, keeping a hint of her original design. EmpathP has stated it's fine for artists to draw her with elf ears or normal ears because of this.
Despite being rejected, due to fan request EmpathP uploaded the original elf-eared versions of Avanna on her tumblr account.
While many assumed that Avanna would be a red-head, Zero-G specifically asked for her to have black hair at the beginning of the designing process. While creating color schemes, other hair colors were given as examples, but inevitably it was decided black hair was best for the character.
According to EmpathP, the reason why her hair was lengthened was because she was requested to make her look more feminine.
While it is unknown why Zero-G chose this name, according to name origins, "Avanna", is a combination of the old English word "Ava" meaning "Breath of Life" and the Latin name "Anna" meaning "Gracious", resulting in the meaning of her name implied to be "Gracious breath of life".
For Avanna, Zero-G seemed to adopt a similar technique to that which was used for Oliver's promotion. Upon her unveiling officially, EmpathP was able to talk directly to the English speaking Vocaloid fans and answer questions about her involvement with Avanna. Most of the focus was on the Avanna topic at Vocaloid Otaku forums and also the topic about her official artwork. This led to bonus promotional art material, EmpathP's "developers diary" and design notes being handed out quite freely.
One of the theories put forward by the artist EmpathP was that the reason why Yamaha rejected the non-anime like style of artwork they initially put forward was owed to the reaction to Bruno and Clara's original design.
According to the artist, in Avanna's early concept design, her height was 5'6" and her weight was 156lbs. The artist had stated that in her final design, her weight is around 110lbs, it should be noted that these are just personal preferences of the artist and not official by any means.