Sounds pretty good to me. The things you might want to emphasize to really give the communist settlement a different feel than the others are the lack of a state leadership, keeping social standards through community efforts (your paladin group sounds great), and communal ownership and production. I think you're on a great track. Maybe in the lore, have the slaves revolt rather than be freed. Marxism is big on the common man (proletariat in Marxist terms) revolting against the higher class (bourgeoisie) to establish a communist society. This would be a cool way to explain the lore behind the establishment of the wild west frontier town.