Re: What do you do when a student is acting rudely in your class.
Well.. sounds like you've tried a lot of ways to handle this. It is necessary to be strong and know when patience is in place, and when it is time to accept the loss and move on.
I am a bit sorry to read all the 'my way or the highway' opinions. I still think Aikido is about forgiveness and acceptance. Practiced on and off the mat, but this is not the same as being a pushover. If you can seriously say that he has been told exactly what types of behaviour you cannot accept, and he continues to do so, then let him now that the next time he does any of these things is - in effect - him writing his own discharge from the dojo.
It might be time to prune the three.. but it's a shame when it cannot be avoided.