I think I've read since that they're not considered canon but I can tell you that when Ms. Cavelos wrote them, JMS gave her his blessing so I do consdier them to be part of the arc... actually they happen BEFORE Crusade so you get a lot of insight into the Technomages and into Galen.

I always thought Gideon and Galen made a better pair than Goidepon and Elizabeth Lochley.