So, I heard that Scholastic would, if the relaunch does well enough, consider releasing a second series of Animorphs books. I don't know how likely that is, or even if that rumor of them possibly considering it is true, but I thought it'd be interesting to look at some possibilities for the new series. I'm thinking honest speculation on what it could really be about.
The big thing to keep in mind, I think, is target demographic. While Scholastic and Ms. Applegate are certainly aware and appreciative of the now older fanbase of the original series, we would not be the target audience. They'll want to bring in new kids; a new audience to become as engrossed in this series as we were as children. Their ideas would be focused on that group.
A second thing to consider would be the timeliness of the relaunch and a new series. Based on the current release schedule it will be a very long time before Scholastic re-releases the entire original series. Assuming it even gets that far the launch window for a new series would probably have already passed. At that point they'll have already gone through another generation of fans for the original series. There may not be demand for new books at that point.
So, considering this, I think the best option for new Animorphs books, if they were to happen, would not be sequel or a follow-up series, but instead a "Secret Files" type series of interquels. Its implied a few times in the original series, especially at the end, that the Animorphs went on many more missions than there are books. I.E. There are references to "hundreds" of missions (despite there being not nearly that many books) and a couple of the books open up mid-mission and then segue into the actual plot for that book. As such, there's plenty of room to squeeze in new books that take place in between the original books.
These would be best for a few reasons. First, this way the new "series" would still feature the original Animorphs and follow, more or less, the same format as the original series. The relaunch will get new fans interested in Jake, Rachel, Tobias, Cassie, Marco, and Ax. New fans will want to follow those same characters. Second, it allows for more new fans who missed the relaunch to follow the series without having to worry about continuity and whatnot. You don't have 60+ books of backstory for a reader to have to worry about.
There are a couple of downsides to this approach, though, especially for those of us who grew up with the original series. Primarily, nothing major could really ever happen. If it did, readers would wonder why it was never brought up in later books (or why its such a big deal in some books, but not others). The missions would have be relatively low-key. It also take away the suspense for those who have read the later books. Do the Animorphs have enough time to demorph? Will Marco make it out alive? Is Cassie quitting the Animorphs for real this time? Veteran readers would know the answers.
I still think, though, that a series of interquels would make the most sense if Scholastic were to commission a second Animorph series. What does everyone else think?