a) not really. Campden is used at the beginning of a batch to forestall any yeast already present on fresh fruit from taking hold, and used at the end to help prevent from oxidation during bottling. Because there's no fresh fruit, as long as you don't splash a lot and use a bottling wand you should be fine. But then again, it wouldn't hurt anything if you added them.
b) I find that if your wine still has that much carbon dioxide dissolved in it, then it can stand to sit a while longer in the carboy anyways. But I don't degas even when I do rush a batch along. It loses a lot of the carbonation racking to the bottling bucket and what is there is already at equilibrium with the outside air pressure at room temperature so it doesn't pose a bottle bomb/rocket risk.