you have to put the things you want to give other soldiers into your baggage.
no body like their soldiers directly take things from his own inventory, right?
cavalries need carbines and SMGs, but to upgrade cavalry you must have melee horseman first.
muskets are also accepted, I put it like this: long muskets can be shortened easily and then used mounted.
maybe you give someone musket but he turns up to be a veteran cavalry with a SMG, I consider he as a experienced soldier who has gained lots of booties, he trades some of his booties and the musket you give him for this SMG from someone else.
Does this assumption make sense? We can talk about this later when I got a child board
After all this game engine is not perfect, we can only do things that in its limitation.