Board Thread:Questions and Answers/@comment-24567858-20140219184613/@comment-1321146-20140220054315

You aren't supposed to know who the other guild's officers are, until you've defeated them once. At that point they get a flag next to their name, so everyone in your guild can see their rank. See the Guild War page for details.

There's no way to chose who gets the officer spots in your guild. They are (discounting the bugs in the system) decided based on deck strength and Total Points earned during that guild war week.