Although it's been a long time since I
read either one, Edmund Wilson's Aplogies to the Iroquois
(the most memorable passage, to me, is a shocking historic account of
French soldiers and native American warriors torturing a captive
warrior from another tribe) may have touched on the Kickapoo
puppets. Possibly, the Native American essays in Wilson's Black,
White Red, and Olive may have information on them as well.
My point is that it's possible Wilson
may have retailed some of his Native American lore to VN purely
conversationally. And we might go so far as to assume that Kinbote's
knowledge was gained in the same academically anecdotal way.
Andrew Brown