I asked JMS this and got this response:
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>Who's writing the Technomage Trilogy? Are you getting/did you get
>manuscripts for the Psi-Corp, Centauri, and Technomage trilogies to ensure
>they're canon?
Jeanne Cavelos, and yes, they're all run past me and our reference editor,
Fiona Avery.
jms
(jms...@aol.com)
B5 Official Fan Club at:
http://www.thestation.com
(all message content (c) 2000 by
synthetic worlds, ltd., permission
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SFX Magazine)
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Mac
In broad strokes, yes, the series is canon, since I came up with the outline
for all the Del Rey novels. And overall, I'm very pleased with how they've
been going.