"1. The widgets page doesn’t allow me to expand the individual widget content blocks.."
This isn’t caused by the Child theme, it may be due to your WordPress settings, User/Admin setting, plugin, code etc. I would check externally since the Child theme doesn’t have that type of control (it only handles design).
"2. The genesis slider disappeared."
Did you add the Genesis Slider widget to a widget area? I don’t see it anywhere in your source code, so I’m guessing either you haven’t added and saved it in a location, or it may have to do with what I mentioned above in #1.
"3. Gravity forms is no longer able to create new forms."
This also isn’t Theme related, so you would need to contact Gravity Forms for any issues you’re having with their plugin since it’s a 3rd Party plugin. Since they created the plugin they’ll be able to know what’s going on much better than anyone else will.