to answer those questions you need to talk with your treatment provider. only you and your treatment providers know how and why your internal system is set up the way it is, how your alters make changes, whether or not your alters can get other alters to come out of the dark and into the light...

for some people it just takes being co conscious to have the ability to share and make changes.

for others it takes therapies like hypnosis, deep relaxation, and other types of therapy that will enable the host and alters make changes in their lives and the internal system.

for others it takes a heck of a lot of work on these traumatic events and triggers that caused the person to create their internal system of alters...

for other....well you get the picture..

each person is different so there is no one way in which the host and alters can make changes and evolve if their system is one that evolves.

there are many good books and articles on how the brain works, and topics like dissociative identity disorder, alters creations and conceptualizations of the internal system. amazon.com has well over 3000 books that are about this disorder. Im sure if you did a search on there you will find all kinds of books that fit what you are looking for. Sometimes what I do is look on amazon for what ever topic I am looking for, take down the book tittle and author, then I check with my co workers to see if anyone already has the book, if not I hit the library and the crisis centers requisition forms for purchasing new books for the crisis center. this way I get the book I need with no cost to me and the crisis center gains a book for their shelves.