Viktor,
Thank you for suggesting diffnow.com! Using it made me step back, stop panicking, and look more carefully at the files. Under careful examination, I found that I actually did have the wrong code in the functions.php file. It's easy to miss something and make assumptions when you're rushing trying to fix a down site! I am happy to say that it has been fixed and the sites are live again. Thank you very much for your help!
