I guess guns will work in the same way as in NW, but maybe range of heavy guns will be increased, and maybe I'll add "Grenade buckshot" (I haven't find English termin for that kind of missile, it is the same as grapeshot, but instead of iron balls it contained ca. 30 grenades, which exploded in some time)
but maybe for game it will be too deadly weapon.
And btw, I think I realized at least where to start to make my own bot-controlled cannons
I can start with modifying code of siege towers - they need bots to be near too
As for weapons of armies of that time. It is common mistake - imagining all Allies armed with rifles and all Russians with smoothbore old junk.
In reality best armed (but not best equipped, with their constant lack of everything but weapons and powder - from warm clothing to food) army in the Crimea was British army, where rifled muskets were main infantry weapon (but 4th Division and Guards were armed with smoothbore muskets), and don't forget - British army was the smallest army in Crimea, and with all their weapons they didn't capture their main objective - Russian 3rd Bastion [Great Redan].
French army was the largest army in Allied camps, and French infantry in general was armed with smoothbore muskets (except for Guards and Zouaves, they were armed with rifled muskets and Chasseurs, who were armed with carbines).
Turkish weapons I haven't research yet (but I've read they had mostly smoothbore muskets), but anyway - they took part in only two battles in the Crimea - Balaclava battle, where they fled at the beginning of action, leaving without fight redoubts with British cannons (British Light Brigade was supposed to re-capture just these cannons, but instead they charged on Russian batteries in other valley), and after that battle Turkish troops near Sevastopol were used by British as workers only and didn't take part in next battles. Second battle, where Turkish army took, part was succesful defending of Eupatroria (most Turkish troops were based in Eupathoria along with small French garrison).
About Sardinians some write they had mostly rifled muskets, and others - they had mostly smoothbore muskets, but there were only 15000 of them, they arrived only in June 1855 and were in reserve all the time, lost number of soldiers from deseases and took part only in one battle - Black River battle, where Bersaglieri distinguished themselves.
And as for Russians - their army was caught in the middle of rearmament, so main infantry weapon were smoothbore muskets, but in each company there were 6 soldiers with rifles or rifled muskets (in scale of regiment and division it is pretty big amount of rifles), and there were rifle battalions, armed with rifled muskets (but I must mention, Russians had older rifled systems, so Russian rifles required more time to reload), so in general, Russian army was armed equally or maybe even slightly better than French army and significantly worse than British army, and so in general whole Allied army and hole Russian army were more or less equall, that's why siege of Sevastopol lasted so long. So in mod Allied and Russian armies will be more or less equally equipped too, some units will have better arms, some worse.
And it is also questionable, how much better were rifled muskets than smoothbore, because smoothbore muskets used new bullets (Minie or Minie-like), which significantly increased their accuracy, so rifled muskets were superior maybe in range, but again, not too much (I've read ballistic research, according to which rifled muskets were not that better).
And as for common belief, that rifled muskets brought victory to the Allies in the Crimean war and in Alma battle in particular - it was British propaganda first, which was later used by Russian generals, to exuse their own tactical drawbacks. I'm sure that is how this belief was formed (and I thought so too, before I started researching that period).