As for the outdoor shower,I cut a piece of foam, like off an egg crate,the correct size and and seal off the cold from the shower head and knobs although in the 20's I wouldn't worry about it much with my trailer.Don't know about the outside kitchen,never had one but I would also try,if possible to ad foam for a break on that also.
The plumbing on my outside shower is in the bathroom on mine,I made sure that the warm air of the inside gets to it and yes,in the beginning, that was the first thing to freeze on my trailer when it was in the teens.
Anyone who camps in the cold will find foam insulation to be your friend for all the outside entrances.