Glad you solved your first issue!
You must closing follow the instructions in this video: https://youtu.be/soEEw4oS7no .
If the bones reset to the original pose, likely you have not saved the new Animation Retargeting Pose (select “Modify Pose”, “Use Current Pose” and save the asset). Remember also that animation retargeting must be done after you modified and saved the Animation Retargeting Pose.