Hello
First, I would recommend to check in the next article for potential limitations:
https://learn.microsoft.com/en-us/archive/blogs/mdegre/can-i-move-sql-server-to-another-domain
Reference: https://social.msdn.microsoft.com/Forums/sqlserver/en-US/02772e08-9c14-4916-8daa-6076178dc669/sql-server-migration-from-old-forest-to-new-forest?forum=sqlservermigration
I would suggest looking at the Active Directory Migration Tool:
Guide:
http://www.microsoft.com/en-us/download/details.aspx?id=19188
ADMT:
http://www.microsoft.com/en-us/download/details.aspx?id=8377
PES (Migrate User Passwords)
http://www.microsoft.com/en-us/download/details.aspx?id=10370
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