Use of the notion of emptiness (śūnya or śūnyāta) is not much in the Lotus Sutra. Of course, all things are empty. But undue emphasis on emptiness can too easily become a kind of nihilism in which nothing matters. In the Lotus Sutra everything matters.

The Buddha works to save all beings. Even poor Bodhisattva Never Disrespectful, who goes around telling everyone that they are to become buddhas, though initially not very successful eventually “converted a multitude of a thousand, ten thousand, millions, enabling them to live in the state of supreme enlightenment.” And he later became the Buddha Śākyamuni!
A Buddhist Kaleidoscope; Gene Reeves, The Lotus Sutra as Radically World-affirming, Page 195