Required Flight Crew Member Question

We’ve been having a discussion around the airport, and I figured I’d ask it here to see what you all think. Two pilots (Joe and Jessica) decide that they are going to go flying (under Part 91). Both are private pilots with airplane single engine land ratings. Both have current flight reviews and both meet 90 day currency requirements. Joe will be flying, but he feels a little rusty. So, before the flight, he asks Jessica to be the pilot in command and she agrees. During the flight, Joe is the sole manipulator of the flight controls. Joe, of course, logs PIC for the whole flight and Jessica doesn’t log anything because the operation only requires one crew member. Who is the required crew member? Is it Joe (as the sole manipulator of the flight controls) or Jessica (the pilot in command)?