Not necessarily true. KA and MG don't own the rights to Animorphs. Scholastic does.
That they do. Which is why K.A. checked with her people at Scholastic before commenting on it.
They were always work-for-hire, yeah, which just goes more to the point: Scholastic has nothing to worry about in terms of creator's rights, they can kick the authors to the curb and go it alone if they want to. They probably wouldn't cut them out entirely, but if they want to, no problem. So it's not like they're walking around on eggshells tippy-toe-ing around whether Katherine & Michael know what they're working on or not. The authors are probably entitled to a royalty check and a "story by" credit and that's about it, if the company wants to be dickish about it all.
If they had something in the pipeline, they'd just go "Yep! Tentative 2017/2018 release date" or whatever. Seems like they pretty much flat out said "nothing's on the cards". Doesn't mean Universal hasn't been scouting the license and stuff, we've known a couple of studios were doing that for about a year or two though. It's only like 10-15% of licensed movies that ever get past that stage, scouting for new IPs alone isn't all that significant. I think a while back Grant said people were looking at Gone, too, that seems to have fizzled out.