If BG movement is not dt related it won't be affected by timescale changes.
Regarding the character change in pose, you must pause your controls when you pause the game. I suggest putting them all in a group and deactivating the group when game is paused.
Both topics and many more are explained in this tutorial by ASHLEY.
https://www.scirra.com/tutorials/67/del ... dependence
You definitely should read it! <img src="{SMILIES_PATH}/icon_e_smile.gif" alt=":)" title="Smile">