Rereading this confirmed my memory that this is the worst Animorph book. There are still a few that could displace it, but this one is REALLY bad. I've never read Animorphs fanfiction, but I'm sure there's fanfiction out there that's better than this book.
I have so many questions. I'll just go into the big ones under the cut.
The entire premise of the book makes no sense. The last time we saw the Pemalite ship, Erek moved it somewhere only the Chee could access it, and there's no worry that the Yeerks will be able to find it again (since the Chee are 1. way more technologically advanced than the Yeerks and 2. know Yeerk technology since they've infiltrated the Yeerk invasion). So this entire mission is moot. Why do the Animorphs even bother?
There were several instances of continuity errors that happened within paragraphs of each other. Rachel saves Jake in orca morph, but no she's actually one of the sperm whales (because there are two and only she and Tobias have a sperm whale morph). Marco is yelling about holograms except no he isn't that was you, Jake, one paragraph before.
Thank everything this is this ghost writer's only book. Everyone is so out of character, it was painful to finish. You could skip this book entirely and not lose anything story-wise.