I really have no idea about the yellow blushing on Grif, but I am sure the YB gene has a lot to do with it. I know on a "normal" YB, the alien heads are supposed to be outlined in a yellow so I'm sure that's where it comes from. Love it though! For lighting I used one of these.
http://www.paulcbuff.com/b800.php
with one of these
http://www.paulcbuff.com/fob.php
I used to shoot professionally so I have some cool toys laying around that don't see much use anymore.
Dave