Crayak backing the Yeerks? Sounds interesting, you should write a fic about it.
I thought of an idea for it a while back, which included all the Animorphs (including Rachel) going to the HB Homeworld with Toby and her troop after they won the war for Earth. Part of the prologue included rewriting some of the ending so Rachel survives.
The guy that runs the HB Homeworld was going to be Visser Two, but then Book 48 came out and I changed it to Visser Five. I made Visser Five out to be secretly the rightful ruler of the Yeerk Empire. He was the Emporer back when Seerow came, and he was betrayed.
He's been trying to end the war, much like all Vissers, but he doesn't want to enslave everyone and take over the galaxy. He's better than Visser Three, but he does practice involuntary infestation.
There's some other stuff, but this is all quite off topic. I probably won't start any more fics unless I finish CoaAS, which may or may not happen.