Not much response to your questions so far, is it?
BTW, a question is never stupid, only a answer can be stupid.
But you are asking to write a kind of a book about building trough the centuries.
Okay, I try to keep it short.
One way (but certainly not the only way) in which a city can develop is as follows;
At first a wooden motte and bailey castle was erected. (1000-1100). At certain moment this castle could be replaced by a rectangular stone keep. (1100-1200). If the owner is rich enough, he can add walls, towers and gatehouses to this keep. These walls could be built either around the keep, or somewhere against it. In that case, the keep was a part of the curtain wall. Then, additional buildings were risen. A chapel. Stables. A blacksmith. Al these additions resulted in a lack of space within the castle walls. Thus other houses were built outside these walls. But these were very vulnerable to enemies of the castle, of course.
If the lord of the caste thinks this group of houses as important to him he has a second, mostly lower, wall built around them. Thus, a citadel is born.
But it can also be that at first the city was built, and a castle was added in later times.
The Tudor style is a late English gothic style and can indeed be found in walled cities.
I am not very familiar with the noble picking order, so I hope for you that an other CC-member can answer that question.
I hope, this is of any use for you. And as you said yourself, it is advisable to go to a library or something to get some more specific information
"Too low they build, who build beneath the stars".
Edward Young / Night Thoughts.