I've been thinking about something and I honestly believe Deanna's name, besides being horribly misplaced, is actually an inside joke of some sort by the translators/localizers from SOA.
My rationale is that Deanna's japanese name, Shu, is a reference to Shugo Takahashi, the general director of the project, if I recall correctly.
Now, it's a long shot, but I have a feeling SOA went along with the joke here.
I wonder if anyone knows the names behind the translation in order to either substantiate or refute this claim.
Edit: I managed to find a scan of the manual. The production credits are as follows:
Producer: Jerry Markota
Product Manager: John Garner
Text Translation: Sinobu Shindo
Text Editors: Jerry Markota, Sara Reeder
Lead Tester: David Wood
Assistant Lead Testers: Gregg Vogt, Todd Pifer
Testers: Crissi Albertson, Mark Griffin, Joe Cain, Stan Weaver, Tony Lynch, Michael Wu, Conan Tigard, Michael Williams
Manual: John Mclain
Special Thanks: Judi Markota, Michael Deininger, Mikiko Itoga, Wendy Dinsmore, Mark Sherrod, Manabu Akabane
It seems this would disprove my claim (by this rationale, Deanna should have been called Jerry), but I still think there is something else to dig here.