Every 'component' in BulmaJS is its own self-contained plugin. All that is required is the BulmaJS core, this provides basic functionality for each plugin to register itself and also handles the initial DOM parsing and creating of plugins. The core also contains common methods used throughout the other plugins.
You can then build your own bundle by including the plugins you need. The core will be automatically included and never duplicated in your final package.
We would recommend building your own bundle though, as this will provide the most flexibility.