Thanks for your detail information.
1 & 2. Regarding this issue, please try to enable WP_DEBUG to check if there’s an error message occurs in there. About enable WP_DEBUG, you can check our documentation about it here http://support.jegtheme.com/documentation/system-status/ then jump into WP Debug section.
Also, can you please try to disable all plugins except required plugin that related to JNews just for a while and then checks if the problem still persists or not. Because i assume there’s a plugin conflict problem.