Hello,
During my work as part of the support team one of managed hosting provider, I was done dozens of the similar to your tasks. To finish this job successfully we can use 2 different ways:
1) Clone entire system to new place than reconfiguring network settings;
2) Configure new Debian 7 system from beginning then moving all services one by one.
Both scenarios I was applied successfully in past and have owned well-tested solutions. The task promises to be interesting and I'm ready to do my best on it. Please let me know if you're interested.
Looking forward to hearing from you.
Best regards Den aka dundell.