You can get the leaderheads
HERE I tested this so you should be able to get them.
On the subject of governments, I think they work just fine as they are, and I do think there is room for others.
I always choose monachy over republic, most of the civs have monarchy era UUs, so you may as well go to war, cos once you get the
Golden age you can get techs realy quick, plus you can take advantage of the extra production to build cultural achivements. You can capture wonders, expand your borders without reaching optimal city number make peace and get more techs and more money. Even after the golden age, you may as well stay with monarchy cos you should never stop a war untill you have won, I.e reduced your neighbor to a vassal state if they have less culture than you, or assimilate them if they have more.
Ancient and middle age eras are the only time to make war!
The comunism of Civ III is a kind of improved despotism, i.e. totalitarian leadership based on a socialist economy. Facism was totalitarian leadership based on a capitalist economy, or the despotism included in Civ III (see they didn't leave facism out, its just not as good agovernment as some people would like. And historicly facism wasn't a very effective government, remember, they lost the war!)
I personaly use a "Utopian Socialist Republic" which has a "democratic" trade bonus and war wearyness with improved worker speed, comunal corruption, free mainatnece of buildings but expensive army (two coins per unit, for every unit) and no rushing of improvements. This is how I would govern a civilisation in the modern world, falling back on an emergency war government, in case of national emergency.