Yeah well, so I read it and felt that I have arrived at a point way past caring about where this fits into continuity and which character is missing (ah well, I noticed Jacques and Cham missing from the group shot but hey, maybe they were ill that day). I tried to enjoy it but the direct violation of the Legion code did not help. Kill that boy nobody has ever seen before... hm...
The story per se is pretty standard in my eyes. It helps that some characters like Star Girl are part of the JL team. The Infinite Man okay, brings up a little nostalgia. And to see the Legion is better than not seeing them at all.
I will - of course - be following it, but I guess the status as supporting cast makes the Legion vulnerable to bad plot elements like: Death, acting out of character or not acting at all. Not much hope here...