Ok, let's all agree on one thing: no Romance culture is properly represented in the game, all of them are reflections of today's views. Romance people in the Middle Ages formed a linguistical and cultural continuum which was in direct continuity with the late Roman Empire (something you can still see today if you are familiar with Romance dialectology, especially in parts of the Romania such as Italy and Southern France). All of the local languages were dialects of the non-standardized late Vulgar Latin; hence all the Latin and Iberian cultures that we see in game reflect labels that we associate to partitions of that continuum using modern lenses and concepts.
Having said this, you are wrong. The Lombards as a distinct group associated with the Germanic invasion (and as I think is conceived in the cultural map that we seen, given that it's associated to the areas politically controlled by the "Langobardi") ceased to exist shortly after the Frankish invasion, for they only constituted local elites which quickly assimilated into the new Frankish dominators. Eventually, however, "Lombardy" became a geographical notion, associated to a specific region in Northern Italy which is today officially the largest one (population-wise) of the country. The "Lombard league" takes its name because it united cities in that area, and the "Lombards of Sicily" were people from that area that Emperor Frederick II invited to move to the southern island. They retained nothing of the old Langobardi, specifically nothing of the language (I am talking of what is today known as "Lombard dialect" of the Italian language).