Rob stark 'king of the north' ability is that he can remove an engagement token before being ordered. The hounds ability is 'fearsome' meaning you are unable to disengage from his unit. What would you do if they (rob and hound) became engaged?

I think that as Rob is able to remove the token before being ordered that this does not count as disengagement and so is allowed to do so. any thoughts?

From the language, removing an engagement token is not the same thing as disengaging, so Robb should be able to remove the token. Then, since there is no token, he would move freely.