Last word from a native speaker of German: Vit-ken-stine. Emphasis on the first syllable.

to yuck: What is sick about it? What do you tell your four-year old when he begins to grapple with the concept of death? How would these children deal with losing their dear teacher suddenly if there was a cover-up or taboo?
4 is NOT too young. They can start coping with their sadness right away, instead of later, and get a great view of serene dying- not up close, of course.