So, I was reading something on the blog that Clay pointed us towards: 

[hider=Spoilers and commentary]
 "No." She shook her head. "Not the way you think. I know I have a son. I know his name is Tobias. But that's all I know. They brought a little boy to me after the accident. A baby really. They told me he was mine. I didn't remember him. I wanted to. I tried to. But I didn't. I don't remember anything of my life before the accident."

 ----Book Forty-Nine, The Diversion

Ifi: Maybe it had to be this way
Ifi: Maybe if Loren hadn't been so badly hurt, she would have raised Tobias and loved him and he'd never have trapped himself in morph, never led the Hork-Bajir to freedom, and never spied out a billion places for the group.
Ifi: I mean without Tobias free to be a full-time spy, the Animorphs probably would never have made it so far. [/hider]

If you don't want to look at the spoiler, in short, it talks about the need for Tobias to be a full-time hawk/spy for the Animorphs. That without him, they wouldn't have the ability to pull off their many raids and operations due to the lack of intelligence (meaning Tobias just flying around, finding odd things or watching people to be sure that they aren't Yeerks). 

So, what I'm getting at here is, the same is going to be true for our group. Someone's bound to get annoyed if one of our characters misses enough school to fill this role. If all our characters start missing school on an equal basis, it'd be suspicious. So, the cold reality is, we need a Tobias. 

Just some food for thought. I'm not suggesting anyone (I've considered Theo for the role before, I'm not sure how I'd make it work though), and I'm not suggesting they need to be trapped in morph. Just available and not bound to school hours.