Actually, that was one of the things that gave me pause. However, I think I've come upon a way to deal with this. And I'm not quite sure he's a Q yet, but he sure is somthing!
Anyhow, my suggested way of dealing with it is this: Write him up as he appears. A human male from Terra who is an excellent helmsman who seems to have an instinctive astrogation. Worry about the rest later on.
The way I'm looking at it right now, I was thinking about doing the sourcebook with information up to the destruction of the Excalibur. Then adding a supplement area right onto the end of it taking into account the new information presented in the Excalibur trilogy which just recently came out. So basically, Ambassador class information in the main section, Updates in an attached supplement.