Defensive structures and civil war/rebellions

[Beorn]

I have been playing my first "serious" game as Dacia, and making liberal use of their faction advantage of strong defensive structures. Now that I am approaching the mid-game, cities are getting larger, loyalty is a bit more of an issue, and the possibility of eventually falling a civilization level looms, and it occurs to me...

If a rebellion occurs, it will be the rebels inside that nigh impregnable city.

So before I react strategically, I want to check with those who have more experience with the game. Am I basically correct that rebels get the defensive structures, in fully working condition? Am I correct that these rebellions are initially un-resistable, that a garrison might discourage rebellion, but if a rebellion occurs it automatically holds that city? Am I correct that the only real defense against this occurring is loyalty, that high loyalty cities will not rebel? So that it is extremely important for high defense cities to also be maintained at high loyalty?

[13obo]

Just yesterday night I had a civil war with rome where 2 usurpers spawned in south italy and carthage areas respectively. I can confirm that the usurpers get a chunk of a few regions from your empire around the area that has troublesome loyalty and keep all buildings inside. They also spawn with an army.

However, your army in the area is retained by you and doesn't flip even if in a region that flips to the enemy (i. E. Only the garrisons switch sides by virtue of being a part of the region).

So to answer your question, yes, you'll have to reconquer those fortresses.