Adding a 2012 R2 Domain Controller to a 2008 R2 functional level domain

Our current domain is at a functional level 2008 R2 and all the current domain controllers are built on Windows Server 2008 R2 OS. One of our remote site domain controllers is up for replacement and we are looking at deploying a domain controller with Windows Server 2012 R2 OS.

Are there any "gotcha's" or things to be aware of? I understand it will likely bring the domain level up to a mixed mode but is there anything that absolutely will not work with this set up? It seems pretty straightforward with just installing the role and then running dcpromo through Server Manager. I remember how difficult the jump from 2003 functional level to 2008 R2 functional level was and just want to be sure running in this mixed mode won't cause an even bigger headache.

I have looked at Technet and not seen anything that seems too difficult or dangerous.

Introducing a 2012 R2 DC to your environment won't automatically update your domain or forest function levels. It will extend your AD Schema but hat change should not cause issues. The ADprep (which extends the schema) does not need to be run from the FSMO role holders like in older versions, so you should be able to just proceed with the role install, then the DCpromo process.

There should not be as long as you do not change functional level until you upgrade all the DC to 2012.