I am not sure which dolls got this face first but the European Sea Pixies gets dibs on the sculpt name. These dolls came with a new body sculpt as well, which was adopted by Kelly and her (new) playground friends. It's a body type with longer arms and legs and bigger feet than the "klassik kelly".

Sea Pixies/Kenzie
Copyright: 2006

L6903 Sea Pixies Fairy, c2007

L6904 Sea Pixies Mermaid, c2007
Photographed through box plastic

Kenzie is the first friend of Kelly's to use this sculpt, as three new molds was introduced in 2008. Kenzie in this version below, doesn't have painted teeth, like the pixies above. I haven't deboxed - or own any deboxed dolls with this sculpt so I can't go further into detail but it is my belief they are the same, from what I can tell comparing them in their boxes side-by-side.

L4376 Sunflower Park theme Kenzie, c2007
Photographed through box plastic

The I Can Be sets have featured some no name kids and in the Swim Teacher set there were two girls with the Pixie head mold, one brunette, one blonde in rooted pigtails.

M1463 I Can Be - Swim Coach kid, c2008
Photographed through box plastic

M1463 I Can Be - Swim Coach kid, c2008
Photographed through box plastic