Replacing two 2008 R2 Domain Controllers with 2012 R2

Hi,

I have been tasked with Replacing our 2008R2 Domain Controllers with 2012 Domain Controllers. I say replace because the 2008 will not be an in-place upgrade.

As of this moment. I have :
- created two new 2012 servers - Patched them up - upgraded vmware tools etc ( yes they are virtual - VMWARE ).

And thats about where i sit.. haha

I was looking for assistance from people who have upgraded / replaced their DC's.  Better yet : DOCS perhaps they ahve followed.  I understand each business is unique.. and now docs will work for everyone.  There's so much out there Im not sure which docs to trust ..etc.

I have found this :
http://blogs.technet.com/b/canitpro/archive/2013/05/05/step-by-step-adding-a-windows-server-2012-domain-controller-to-an-existing-windows-2003-network.aspx

However questions enter my head of - when do I make the 2012 servers actual domain controllers.  Do I eventually give them the same Computer name as the ones I will be replacing - when is it safe to remove the 'old / currently used' domain controllers. How do i know everything has been transferred over etc ( granted this will be different for everyone ).