A trustable source has revealed that the Tik Tik Boom demo did not include GRL's vocals after all. The vocals were done by Onique "Sparrow" Williams, which is one of the writers of the track.
This could lead up to think that the song was actually not meant for GRL, but that has not been confirmed.
This YouTube video is only for reference. The info comes from 2 different guys who collect reference demo tracks and are very active on Genius and Soundcloud.