This all rings true except the one highlighted statement - visceral pain usually is poorly localized and parietal pain tends to be more localized. Hollow organs don't have nociceptive neurons, so they cause referred pain - anything in the midgut will hurt vaguely around the umbilicus, e.g. Inflamed peritoneum hurts where it is actually inflamed, and will also result in the traditional s/sx of peritonitis like rebound tenderness and involuntary guarding.
The archetypal model of appendicitis says it all: early in the course, before peritoneal inflammation has occurred, pain is experienced as vague, crampy, periumbilical discomfort. As peritoneal inflammation progresses, pain localizes to the RLQ, with pain in the RLQ even when other areas are palpated or manipulated.