Will Rey take apprentices in Episode IX?

[FaxModem1]

On the plus side, in the old EU, and in Clone Wars, the Clone Troopers were given names, bars, and certain rights by the Jedi, who wanted to treat them like people as much as possible. Even trying to give them a fair shake whenever possible. Note how much this differs from the Kaminoans, who are rather puzzled by it. Though, it might be akin to a horse breeder being rather puzzled that the person who legally 'owns' the horse is talking to them and treating them like a friend as opposed to just a living vehicle.

Did they have the right to leave their positions as Clonetroopers?

Iunno, if any such plan existed for them to do so after the war, it was kinda rendered moot when the clones shot them all.

[Gandalf]

So slaves, but sometimes their slavemasters treat them nicely before using them as cannonfodder?

[The Romulan Republic]

So slaves, but sometimes their slavemasters treat them nicely before using them as cannonfodder?

Yes.

And the droids are slaves. And the humanoid slaves on various backwater worlds like Tatooine and Canto Bite. And the child soldiers the First Order recruits. They're all slaves.

In ten years or so, when they make episodes 10-12, it should definitely be Star Wars: the Great Slave Revolt.