everyone has thier own idea of what a good charity should be but i am really seeing a pattern of three mian themes
children
animals
babies .

why not if EBay agree..do something like this
auctin the prizes on ebay by whatever means is liable to raise the most amoutn of money
then split the money raised three ways

have three more treasure hunts. each one aimed at one area mentioned above.

then whoever wins the treasure can nominate thier chosen charity. even teams can do it then