I have some minor flavor things, mainly relating to positions.
Militia Commander/Captain - Renaming them to Colonel and Sergeant, respectively (as Lieutenants are already part of the "regular" army for the settler civ.) To my knowledge, most colonial/western militias (at least from my barely-there knowledge of North America's Colonial and western time-frame,) were lead by a Colonel, and it's less of a mouthful.
Chief Doctor - Nitpick, but Town Doctor sounds more appropriate.
Law Enforcement - Removal of the Judge and Magistrate. They're redundant with the Sheriff and Marshall doing the same job with more appropriate titles.
Optional Hostile Civs plugin
Savages - Evil version of the Natives based essentially of the cannibal tribe stereotype, who share much in common with the cultists as they worship twisted, evil visages of the nature spirits. However, unlike The Cult who find many questionable/abhorrent acts to be personal matters between involved parties, Savages engage in slave-taking and cannibalism with a readiness that makes even some Cultists a little creeped out. They do have a single good trait though: Treasonous sorts and Oathbreakers are rewarded much the same as among more civilized people - the executioner's axe. As they need victims for their cannibalistic rituals and as slaves, they share a babysnatcher role with the Cult, as they're the only ones willing to put up with them. Active year-round.
Bandits and Outlaws - Civilized folk always have criminal elements, and some are better organized than others. These ne'er-do-wells set up shop in frontier regions away from the rule of law, preying on the isolated communities thereabouts. Evil version of settlers, who readily engage in theft, assault, and slavery. As they're more focused on taking your shit than taking your people, they are an overt (that is, non-skulking) [ITEM_THIEF] civ that will ideally attack early, and are active in Spring, Summer, and Fall (after all, civilized folk try not to wage war during the shitty part of the year, and they're still nominally civilized fellows.)
Creatures - based on a combination of folklore, mythology, and urban legends.
Wendigo - Non-megabeast. Best described as some bestial emaciated... Thing, this strange monster is found mainly in the forests, believed to be former natives who became greedy or consumed the flesh of men without sanction from the spirits (or protection from demonic ones.) Larger than a man, slightly faster, and mainly attacks by clawing and biting. While not immune to most status effects, their hunger for human flesh is so overpowering, that they are utterly fearless and go berserk at the sight of potential prey. Generally found in groups of 1-3.
Chupacabra - Semi-megabeast the size of a yak. Very strong, reasonably quick, bloodsucker. An unexplained horror that dwells in more arid places. Usually it will attack a settlement to feast on the blood of the livestock, and while its movements are largely clumsy and unrefined, it can be strangely difficult to hit. No natural skills besides dodging. Fearless and emotionless.
Thunderbird - Megabeast. Believed to be a relative of the Roc, this massive bird of prey is seen through the plains and forests of the new world. Roughy half the size of Roc and can be tamed, with effort.
Melonhead - Nonmegabeast - A more overtly hostile, surface-dwelling gremlin. The size of a large human child, Melonheads have strangely shaped heads and are known to tamper with machinery and occasionally attack people. Typically found in forested areas.
Wampus Cat - Semi-megabeast. A large and vicious cousin to the common cougar people. They are exceedingly rare sights, able to overpower a man and tear him asunder easily. Natural unarmed combat skills. Generally make their lairs in grasslands and forests.
Thoughts?