For me it's 1 hand sword, carbine, two bundles of ammunition. Trust me I can go through a dramatic amount of bullets in a single battle, definitely sieges. A good onehand sword can do 35+ in a swing multiply from the speed of the horse.. instant kill vs anyone who is not wearing heavy armor. There are no cross breed style swords like on Warband, though Broad swords seem to be almost as long as a two hand and to me make better cavalry swords than Sabers on Fire & Sword.
I'd suggest just wearing good armor, you will not need a shield if you're good at blocking with your weapons, relying on a shield can be a tad dangerious. Shields were great on Warband, but muskets do so much damage per shot that I do not see a reason for them, since in melee combat you dont' really need a shield, I only used one to stop walls of arrows. If you're on horse back a lot you should either be a dragoon with a musket/sword, or be a fun mix, with sword/lance/firearm. Throwing shield out just allows you to be dramatically mutli rule. If anything you can carry a two hand sword for foot combat, and a 1 hand for on a horse if you get knocked off your horse I mean.