I have been watching the progress of this. You are not getting anywhere and seem to be spinning in circles.

Another approach to asking and matching things up:
Code:
ls -l /boot/grub/themes/descent/theme.txt
grep . /boot/grub/themes/descent/theme.txt
Because you say Grub2 is having a problem finding your theme file.

With that line in the /etc/default/grub file (for Grub2 theming), Grub2 does not care where it is located, as long as it can find it, and read it. It does not need to be located in a specific directory tree. But the path-to and filename need to be correct and accessible. It also needs to be on a filesystem that Grub2 can read natively.

Please confirm that you can do this manually, before gong on...