Originally posted by: vtpeters
I remember Lucas explaining in some ROTJ Making Of documentary that the Ewoks were at one point in the development of the script supposed to be Wookies. In Episode III we finally get to see an Empire vs. Wookies battle...

They were in the early drafts for Star Wars. Funny details (after the facts) are that the wookiees/ewoks were called "jawas" and they had a princess named "Jamilla".
The fact about the early drafts does not counter that the Ewoks could have been chosen for inclusion into ROTJ as an opportunity to sell merchandise.

GL created many plot elements and names for the drafts, that have been used (and reused) here and there in the various movies. Even the opening space battle and the disintegrating ship in ROTS can be traced back to an early draft.
However, none of the drafts contains any story that tell ESB or the prequels, only disparate elements. GL must have made it up as he went along.