Pikes were still fairly common in the Napoleonic Wars as weapons for militia members, niche anti-cavalry weapons, or just ceremonial aesthetics. This would make a unique melee-oriented class and the proper counter to cavalry once they are added. While the Flag Bearer can serve this role to a small extent, the pike would be much better suited for melee combat.
While carbines were mostly found with cavalrymen and artillery crews, there were groups of skirmishers who preferred them for their compact size and ease of use. This class would be almost identical to the Light Infantry class, but with the carbine taking the place of the usual musket. The reload speed and aim time would be even faster than the normal Light Infantry class's planned reload speed bonus. Since carbines typically didn't have bayonets, the Carabineer would carry a sword.
Although somewhat niche, the Napoleonic Wars saw the continued use of Wall Guns; giant muskets (roughly 75 caliber or greater) with a very hard punch. The army variant of this class is equipped with a full-length wall gun that fires a standard ball while the navy variant uses a cut-down version that fires shot. Both types of Wall Gunner are only able to use their wall guns while resting it on a surface, such as a wall, or by taking some time to use their unique class ability: setting up a gun mount that greatly increases weapon accuracy and stability. As an alternative method of implementation, Wall Guns could be carried from spawn like a ladder or rocket launcher and deployed at compatible locations.