Distributable and license?

I'm building a plugin that will be distributed publicly through the WordPress plugins directory. The plugin will be free, and will be used to connect to a commercial API-based service.

I am using MB to set up that plugin's settings page.

Your FAQ says:

Yes, you can use plugins in your premium, commercial products...

1. Is there a distributable library I can include in the plugin that will avoid requiring to explicitly install the MB plugin?

The FAQ goes on to say:

IMPORTANT: You cannot include plugins in your free products or release/deliver them in public.

1. Given my scenario above, with the plugin itself being free, does this mean I may not use MB in my project?