I think the four elongated fingers are just 'amplifications' for the stage, so they can be seen more easily by the audience. Guan Yin is revered in China! Her appearance is varied. This thousand arm and eye performance is very cool...
"One Buddhist legend presents Guan Yin as vowing to never rest until she had freed all sentient beings from samsara, reincarnation. Despite strenuous effort, she realized that still many unhappy beings were yet to be saved. After struggling to comprehend the needs of so many, her head split into eleven pieces. Amitabha Buddha, seeing her plight, gave her eleven heads with which to hear the cries of the suffering. Upon hearing these cries and comprehending them, Avalokitesvara attempted to reach out to all those who needed aid, but found that her two arms shattered into pieces. Once more, Amitabha came to her aid and appointed her a thousand arms with which to aid the many."
http://en.wikipedia.org/wiki/Guan_Yin