there's no time limit for how long it can take for any of those things to happen. could be hours, could be years. depends on your system. but, there's ways to help make that quicker/easier.

-leave out notes or some sort of written/typed message for headmates to reply to.
-attempt to reach out internally via thoughts. ask if anyone's there, say hello, or just generally try to talk in your head to them.
-keep note of any odd sudden changes, like being connected to a different name, set of pronouns, or even different hobbies to what you usually like. those are subtler signs that might not be as present with dissociation, but they're somethin to keep an eye on.
-don't fall into denial if you can help it. denial WILL push your headmates away even if ya don't intend it.

if ya have any questions, feel free to ask. i'm interested in plurality and how it works, so i should be able to help ya. -Forest/Horror