In the current update of 0.16.1 (for the google play version of mcpe) the skull and wither boss textures are using default textures instead of the fantasy ones
The picture attached is of the recourse pack being activated
https://youtu.be/Cp2esn1mF2o is a link to a video with the bugs because this place doesn't want a 300 mb video
Fixed in 1.0.0 or earlier - The skulls section of the resource pack has been added now.