Kurt Busiek, Chris Kent, and the Legion

From a CBR interview with Kurt Busiek, regarding his Trinity series, which touched on his "Last Son" arc:

CBR: Let’s talk about your run on “Superman,” specifically a continuity question that has been nagging some fans. In “Superman,” Clark had many adventures with his adopted son Chris, who was introduced in the “Action Comics” story “Last Son.” There were a lot of delays in completing that storyline, almost a full year. At the conclusion of “Last Son,” Chris left Earth, seemingly after only a couple of days. Yet he took part in numerous adventures in your title, “Superman.” Was this just plans gone wonky, or is there another explanation?

Busiek: The continuity is definitely a little awkward. If you just read the “Last Son” arc it seems to take place all at once. However, in between Chris Kent’s arrival on earth and his disappearance at the end of the [storyline], he mentions that he got to meet Robin. That’s something that happened in one of my arcs. Clearly, there must have been room for more stuff to happen in between the major events of “Last Son” than it appeared.

The delay on “Last Son” really messed up a lot of stuff. I wasn’t originally going to use Chris Kent as much, but [“Action Comics” writer] Geoff [Johns] couldn’t use him because his story was in limbo at the time. So I was asked to use him just so it didn’t seem like he'd vanished completely.

Originally, I think he was going to stick around at the end of “Last Son” and leave at a later point. I think that later point involved the "Superman and the Legion of Super-Heroes" story, but as it turned out that story came out before “Last Son” concluded. Whatever Geoff had planned for Chris in that other story wasn't able to be done because he needed to get “Last Son” finished before he moved forward with Chris, and so events that should have already been shown, and should have been able to bleed over into other arcs, couldn’t, because of the schedule snafus.

So bottom line: Chris Kent came to Earth, became a foster child of the Kents, did all the things he did in my stories, and then got lost in the Phantom Zone at the end of the “Last Son” arc. And, as far as I know, that's where he is now. But I might not be the right guy to ask. I simply worked with the information I was handed at the time, and when the information had to change because of the delays, I was already done, and Geoff was the one with the headache of figuring out how to solve it.

Wonder if Mon-El (any of them) met Chris Kent in the Phantom Zone? And I wonder if he'll show up in L3W?