From the experts:
Kiki is one of the Coco-Gigi-Fifi-Lulu bohemian-type French nickname names from the turn of the last century, which have endless energy and sparkle. Artist Kiki Smith is its most well-known contemporary representative, and Kiki was the inspiring heroine of Zadie Smith's On Beauty. Kiki can be a nickname for any name beginning with the K sound, from Katherine to Christina to Kayla.
Kiki is also a Japanese name most famous via an anime film, Kiki's Delivery Service.
The notorious artist-actress known as Kiki de Montparnasse but born Alice Ernestine Prin, was most famous as a muse for such Parisien artists as Soutine, Picabia and Cocteau. English singer Kiki Dee was originally named Pauline Matthews.