Hello,
Have you installed the child theme after the demo content import? All is fine when parent theme is activated?
When you switching between child theme and parent theme your widgets and theme options could be different because the child theme does not inherit all theme options of the parent theme and the parent theme does not inherit theme options of the child theme.
So, before switching from the correct theme (where everything is correct) you need to export theme options (Theme Options > Export/Import) and then import them after switching. Widgets should be moved to correct areas at Appearance > Widgets.
Regards