cannot add yahoo account to facetime

I updated and (OF COURSE) I have add everyone's emails to their FaceTime. It won't allow me to add their yahoo emails to "you can be reached by FaceTime at" in FaceTime. (We give out the yahoo email address on the kids' accounts for FaceTime and my iPhone. They have iPads.)

I'm in FaceTime. It has my apple ID. When "add an email" it says "unable to verify email because it is already in use"...... Says it on my iPhone when I try to add my yahoo email and my kids' iPads when I try to add their yahoo emails. This should work because it's always how we do it.

If I go to settings, iCloud, then click on my iCloud address for my info, then contact info I can see all their emails and it says "pending". I "resend" and it says "cannot connect to ICloud". I already entered my password after the update....... SHRUG.

What am I not remembering??

I wish I wouldn't have to do this every update.....