You're right. Still, ice release being in Yukigakure isn't unlikely cause it can apparently be anywhere as long as you meet some prerequisites.

Read Kato through, and while he's a good character I think maybe some of the jutsu's are not too good.. for instance the weakness ''it is slow'' doesn't say much about what it's weakness is. If something is slow and impossible to destroy, then it's slowness isn't exactly a weakness is it? Maybe you should take a look at that, however the character is good and the techniques seem to all have a weakness to fire anyway, so I will say he's in. 

If you want, send me a PM with requests for your team, otherwise we'll make it for you if you'd prefer that.