For the first part of this little experiment, I've written up a number of kits that would be useful for playing different kinds of household servants. Note that this takes much more prep work from the DM just as it does for the players—it's impossible for the PCs to be servants in a game where the DM hasn't worked out the power structure of a kingdom, for example.
Description: The groom is a cross between a military and household servant, something above a stableboy but below a squire. They can be common or noble and care of their master's horses is their primary charge. Many grooms eventually find themselves knighted or even given lordships (much as in history, see John Marshall for one such example). Grooms duties may extend as they prove themselves to that of Marshal of the house, which commonly bears the security of the lord and his people as an additional burden.
Grooms may be outfitted to fight when war arrives, and are expected to be at least somewhat knowledgeable about riding. If sent to foster from a noble family, the groom is likely to have had training in a number of mounted weapons.
Weapon Proficiencies: For a common groom, the following list—horseman's mace, knife, dagger, short bow, hand axe, club, quarterstaff, and pitchfork. Common grooms would be unlikely to start play with specialization. After level one they can learn any weapon they like, and specialize as well. Noble grooms—arming sword, horseman's mace, horseman's pick, spear or lance (depending on period), horseman's flail, knife, dagger, hand axe. Noble grooms are commonly specialized in one weapon, generally a spear or other horseman's tool.
NWPs: Grooms must take the animal handling, animal training (horses), and heraldry proficiencies. Noble grooms must buy etiquette. Any others (if they have additional slots) are up to them. All grooms receive riding for free.
Equipment: Common grooms begin play with whatever equipment their lord sees fit to provide. This often, but does not always, include a tabard and cloak, and weapons of some sort. To simulate the general reliance of a common groom upon his lord, return any money not spent over the amount of 3 gold pieces once equipment purchasing is complete. Noble grooms may begin play with whatever they want and can afford, as the money comes from their parents holdings. They may (15% chance) also receive the benefit of a small rent income from their family, generally 2d20 gold pieces a month.
Special Benefits: After displaying some great prowess in battle, grooms are commonly made into knights or even promoted to be Marshal of the House. All grooms receive free food and board (like most servants) for as long as they continue to serve their lord. Additionally, when wearing the arms of their lord they are granted a +2 reaction bonus when interacting with those who also like their lord (though they may be penalized if the subject does not like their lord). If they are to go into formal battle, their livery and armor will be purchased by their lord—a shirt of mail, shield, and weapon of choice. Upon being knighted they are presented with an arming sword and a suit of mail. If they have not been knighted by level 5, they are knighted then. If they have not been granted titles and lands by level 9, they receive them then as per a normal fighter.
Grooms are much more likely to attract horsemen and knights to their cause than other types of followers.
Special Hinderances: To receive any of their benefits, the groom must remain faithful to his lord. Common grooms have no further hinderances. Noble grooms must spur themselves onwards to ever more dangerous tasks in hope of recognition—they live for promotion to knight or Marshal, something common grooms generally do not take into account.
Wealth Options: As per a warrior.
Races: Most commonly humans. Halflings and gnomes cannot ride and so make poor grooms of this kit, though they may still serve in the stables.