Primosten is one of my favourite small towns on the coast. I am sure that you would love it.
You mention Zadar and Sibenik, but seem to be prefer smaller places. Look at Biograd na moru. It is between Sibenik and Zadar. It is also the most family friendly places on the Coast IMO. It has everything you would want and is in perfect location if you are interested in visiting some stunning national parks, including Plitvice and Krka NP.