I am a bit... confused in regards to urban life and organization in Westeros. On one side you have highly developed urban centers like King's Landing , Oldtown and Stony Sept; On the other, their administrative characteristics do not (through a cursory observation) resemble much of what I know of Medieval urban centers such as the HRE cities.
Are all westerosi cities and towns held directly by some lord? Mitgh there be some sort of oficial city councils in at least some of them, be their membership elected, inherited or something else? What sort of rights, privileges, protections and duties would a westerosi living the urban life have that a peasant would lack? How influential you think are guilds on westerosi urban politics and how they exert that influence?
You have put your finger on the button of an issue that's been bothering me about Westerosi cities for a long time. On the one hand, these are all cities that we know have urban charters - and we can see some areas in which those charters are functioning, in that these cities have walls, they have markets, they have warehouses, they have ports, and they have guilds and guild charters with guildhalls and the like.
What we do not see at all is any form of municipal government in any Westerosi city - King's Landing is directly ruled by the royal government, Oldtown is directly ruled by House Hightower, Lannisport by House Lannister, and so forth. The closest we've seen to a city council is various informal pressure groups of master smiths who liased with Tyrion about the boom chain.
So it seems like, when it comes to political rights, Westerosi urban charters are probably much more limited than their historical counterparts, largely because GRRM didn't want to write about city councils. Now, there are definitely urban officers, especially when it comes to collecting taxes and running the ports, but they would be appointed by the ruling lord of the city rather than being elected. Moreover, there seems to be a tendency for these officers to be selected from the ranks of younger sons of the nobility, scions of cadet branches, etc. But their subordinates in the bureaucracy are smallfolk, and sometimes they manage to scramble upwards.
In terms of burgher (or borough) rights, the fact that Westerosi cities are so demographically enormous suggests that there is a strong appeal for the smallfolk to move to cities. This suggests a certain amount of social opportunity, so urban residency probably means a freer legal and social status - they're definitely not serfs, but then again I don't think most Westerosi peasants are either. But "What sort of rights, privileges, protections and duties" are remains a bit vague.
As to the influence of guilds, it's definitely weaker than in Essos or actual medieval Europe, but it is there.