General Chicken publishes a plugin in the wordpress.org repo: Change Admin Email Setting Without Outbound Email
As of WordPress 4.9, the administrator cannot change the site admin email without outgoing email setup on the server, and recipient email credentials. This plugin restores the admin’s ability to change this setting without sending a confirmation email.
Yes. You can restore previous changes made on “pages”. By default, WordPress has two post types. You can also have custom post types called anything [i.e. tickets, or calendars etc.]. The two default post types are “posts” and “pages”. Pages have a screen option called revisions which allow you to browse through previously saved pages. You can restore any previously saved post if you have the role “editor” or above. This feature can be enabled on any post type by a developer, and is enabled by default on pages.