How to customize (enable/disable, order) the main menu tool items?

You can easily disable/enable unwanted items by changing the menu item configuration.

Keep in mind that if you add your license it'll automatically hide all tools/features that are not part of your subscription, so you actually won't need to touch the menu items at all if their default configuration, e.g., their ordering, fits your needs.

A detailed walkthrough can be found in the corresponding SDK documentation.

PhotoEditor SDK: iOS, Android, React Native, Web and Flutter. 
VideoEditor SDK: iOS, Android, React Native, and Flutter