I have made a chocolate fudge cake and filled with chocolate mousse. Can I freeze the filled cake overnight, take it out in the morning, put the icing on it, take it to work and let it thaw until we are ready to eat it?

Will this damage the mousse? Will my icing fall off as it thaws?

I wouldn't freeze it overnight. Just put it in the frig. Make sure it is covered well and bring it to room temp before icing and you should be ok