Are the hooks in the dashboard such as “load-$page_slug$” and “admin-head-$page_slug$” reliable and consistent throughout installs?

I’m not exactly sure, if I get your question correctly, but… Yes, these hooks are native WP hooks: admin head-(page hook) load-(page) So if you create such page on given WP instance (for example you create it with your plugin/theme and that plugin/theme is active on that instance), then these hooks will get fired. Of … Read more