Nobility, Offices, and Social Structure

I've been working on systems of noble ranks and court officials, but my historic research didn't get me anywhere. There's only some vague speculations that are just as good as my own at best. But if experts don't know, than anyone else doesn't either, and I just can make stuff up.
At least, evolution of social divisions is a bit of a speciality of mine that I picked up at University.

I think there should be several different systems according to the ethnic groups:
Wood Elf Society
Dark Elf Society
Lizardfolk Empire Society
Western Human Society
Arctic Human Society
Gnome Society
Kaas Society

These would have to be reasonably well established.

Origins of Society
The basic idea is that the societies of the humanoid people began when the fey people abandoned their castles in the World of Mortals and humanoids could move freely through the regions that were previously too dangerous, but also had all the good farmland. The nomadic family groups would eventually gather in these places and start their own small farms.
Some of these farms would turn out to be more successful, which made their inhabitants more healthy and better at fieldwork. With a surplus of food and manpower, they could invest time into developing and improving their techniques and expanding their fields. Families that were doing not so well would marry off their children to families with enough food to feed some more mouths, or would seek out employment on these bigger farms. At the same time, people would see that they had a much better chance to survive raiders and wild animals if they banded together, becomming to large a force to easily attack and rob. This would result in the first villages, in which those farms who had the most strong fighting men and who could share some of their food during hard times would have the most power. The large farms can do fine with one or two small farms cutting ties with them, but the small ones could not afford to be on their own. Villages within a valley would form ties with each other and many of these valleys would band together in bigger alliances that would become the Clans.

Ranks and Offices
Headman: The headmen are the representatives of their villages. They are commonly elected through consensus by the heads of the most wealthy farms to deal with things that affected the village as a whole, often for a specified period like one of five years. The major factor to be elected the headman is to have respect and influence in the village, which usually means to have a large farm and taking an active role in the community. A headman does not have a special residence but lives on his own farm, which is usually located near the village center. Anyone who is the head of a family can become the headman, but Lowborn people almost always lack the respect to be considered a worthy candidate, unless they are very well known for their great wisdom and often asked for advice.
Sub-Chief: The sub-chief is both an office and a rank. The duty of sub-chiefs lies mainly in overseeing the security in one part of the clans territory at behalf of the chief, training and equiping warriors, patrolling the surrounding lands, and maintaining fortifications. While mostly defined by their duties to the chieftain, most sub-chiefs come from an old local warrior family that holds the office through many generations. In theory, chiefs can remove their sub-chiefs from their office, but if they refuse to give up their position this always carries the risk of other sub-chiefs siding with them, greatly damaging the chiefs reputation and inviting challengers to the leadership of the clan. As a result, sub-chiefs can be highly autonomous, but if they push their disobedience too far, they force the chief to remove them to protect his power.
Sub-chiefs have to be at least Clansmen though many of them are Highborn as well and in fact make up the majority of the Highborn class. Sub-chiefs will often reside in small castles but if their families are particularly rich landowners they may also live in their family estates. Towns usually form near or around these castles and estates.
Chief: Chiefs are the leaders of their clan, having a claim to their power by being the head of the largest and wealthiest family in the clans territory. Even more so than the sub-chiefs, chiefs need to have a direct line to the founders of their clan as their role often is ceremonial as well. For most clans, their shared identity comes from the original agreement that the clans founders made with the major spirits of the clans territory when they first arrived in the region. While the position of the chief often changes between families, they all need to be regarded as descendants of the founder or at least one of his companions who arrived with him in this land. Outsiders can later join the clan and live on its territory, but for the original pact with the spirits to be maintained, the clan leader must be the descendant of one of the people who made the pact.
High Chief: In the last couple of centuries, since the fight for farmland came less pressing and power struggles shfted to control over trade and rare goods, single clans often have it found impossible to defeat and protect against their enemies, leading to the formation of many alliances between clans. In many cases, these alliances would include many clans of very different size and power, effectively making the smaller clans vassals to the more powerful chief. Usually this would result in the allied chiefs selecting one of them as their military leader, who would become the high chief or king. Since their role is mainly military, high chiefs generally don't interfere with the internal affairs of the other clans of the alliance, but they often have the power to make very considerable demands of the other chiefs is it is considered neccessary for the military readiness and the defense of the alliance. The position of the high chief depends entirely on the acceptance by the other chiefs. While there is some chance that a high chief can force a smaller clan to remain in the alliance through military action and replacing its chief with another sub-chief, this is very rare and risks the entire alliance falling apart. It does however happen quite frequently that the chiefs will not elect the heir of a former high chief to be their new leader and sometimes there are even new elections while the high chief is still alive. In those cases, there is usually a lot of plotting and conspiracy in secret, often for years in advance.
Supreme Chief: In some cases chieftains can become so powerful that they will even get other high chiefs to swear allegiance to them. These leaders are called Supreme Chiefs and there are currently only two in the Barbarian Lands.

Marshal: Since chiefs as political as well as military leaders, they often have to deal with a lot of everyday management and legal matters. The marshal is one of his advisors who exclusively deals will all military matters. He oversees the readiness of all the clans troops, keeps track of the forces of enemy clans and manages the defense of the chiefs personal lands, just as a sub-chief. However, he is usually given authoritiy to speak on the chiefs behalf in all military affairs, making him superior to the sub-chiefs. While most marshals are brothers or cousins of the clans chief, they can be from any background, but being given this position automatically elevates them to the rank of a full Clansman.
Seneschal: The counterpart to the marshal, the seneschal is the main advisor and deputy to the chief in the administration of the clans territory. Many chiefs prefer to only be given regular updates of the state of the land and leaving most of the day to day work entirely to the seneschal. Accordingly, the position includes tremendous amounts of trust as any mistake or threachery can cause much greater damage than the most incompetent marshal.
Magistrate: A magistrate is an official, usually appointed by the chief, who is the judge for all criminal trial within one district of the clans land. Magistrates are not common in all societies and their duty can be performed by the elders of a village or a sub-chief.
Constable: Constables are found almost only in towns where they are in charge of the town guard. They are equal in rank with the other Lieutenants of the local sub-chief.
Shaman: Virtually every community has a shaman. In very small and isolated places this duty may fall to the head of the family or his wife, but most villages have a dedicated expert who deals with the spirits of the surrounding fields and forests. Since the duty of a shaman include the protection against misfortune and the breaking of spells and curses, they are often trained healers as well, since both activties often go hand in hand. Because the tasks performed by the shaman are vital to the village, shamans always have at least one apprentice. In larger communities, apprentices my be much more numerous and rivial or even exceed many village shamans in magical power, but they all follow the head shaman as assistants. Only in the largest towns and cities can one find shamans working idependently of each other.