Alright, my races from this question (Rail Transportation with Races Described Below - Specifically, Seating) are going to war. However, combat works differently here. They lack gunpowder weapons smaller than a 4-foot-long hand cannon (Used by the Na'vi). There are rifles small enough for a human, but these are very expensive, basically too expensive for anyone but nobility, and even they can't afford more than a single gun per family line. By the way, this is for a Dungeons and Dragons game.
I'm basically asking for what combat and warfare would look like using 19th century tactics and gunpowder, but without the muskets or rifles every 10 feet. The main groups of combat are:
Hand Cannoneers: This group is basically just a bunch of Na'vi running around with hand cannons (Imagine a bunch of 10 foot tall people charging at you with hand cannons when all you have is a sharp piece of metal on a stick)
Mages: 5th Level Dungeons and Dragons Wizards (Mainly Evokers) who cast Fireball a few times (I'm planning on using the Spell Points Variant in the Dungeon Master's Guide), before retreating and signaling to some reserve mages to go in.
Knights: A group of soldiers, essentially West European knights, who went obsolete with guns, but with only the richy rich and Na'vi having guns, they survived, and they get equipped with a rifle.
Archers: Soldiers running around with bows. Mainly the larger races use them.
Crossbowmen: People with crossbows. Mostly smaller races (Like the Mitarn, Maer, Humans, Miqo'te, and Avandra).
Calvary: Soldiers on horses. Many of the soldiers in the Taur Races (Leonar, Ashara, Centaurs, and Zavran), along with most Mitarn (Raptor) soldier are here, also.
Battle Elephants: Not actually horses, this is a Direhorse (From the same Avatar as the Na'vi) with a Na'vi rider, and a howdah containing smaller races (Like the Crossbowmen).
Proto-Air Force: Another Na'vi niche troop, a Na'vi with their personal Ikran (Link: https://james-camerons-avatar.fandom.com/wiki/Mountain_Banshee, goes to Fandom Wiki page for the Ikran) with a few smaller soldiers strapped on (Or a second Na'vi) armed with bows, crossbows, or Hand Cannons.
Airmen: A bunch of Pterians, Drava, or Ashara (All Winged Races) flying in the air with bows.
Soldiers: The bulk of the army, regular men and women, all armed with a few spears, a shield, a small sword, and a dagger.
Okay, I've given you the troops. Question: How would a good 19th century general use these troops to gain an advantage, 1800s style?