Remember that the world of Paradigm City is somehow a production. A show. The tomatoes populate that production, but there are implications that they are not- or at least, are not INTENDED to be characters. The only ones that are guaranteed to be "real," or at least, not fabricated by Paradigm, are Roger and Angel. What they are isn't really known, but they have titles like "Director" and "Producer," which implies that their existence are important to Paradigm as an entity, even if they are not actually PART of it.