If you wish to proceed with Pro version start from the detailed description what do you need to achieve, to what plugin (download link) do you need provide access for editor. If that’s a premium plugin I need access to its copy in order to check what real permissions it requires. You can share plugin copy with support [at-sign] role-editor.com via DropBox or similar service.
In general user of Pro version can check what permissions required by some plugin for access to its menu items using “Admin menu access” tool. Open it for ‘administrator’ role and look what capability protects what menu item. Then grant that capability to the other role.