The order question's a classic one for J.D. Robb's series. I can never keep the novellas straight, honestly. The most reliable method I've found is the author's official website—they have a dedicated series list section that gets updated with every new release, including the in-between stories. Forget random fan sites; their info is often outdated.
I'd also recommend checking the Wikipedia entry for 'In Death' because it's usually meticulously maintained by fans in table format, split into core novels and anthology inclusions. For physical collecting, the publication order printed inside the newer paperback editions is foolproof. My shelf is a mess because I started mid-series and had to backtrack; getting the sequence right from the start saves so much headache. The audiobooks on Audible are also numbered, which is a lifesaver for listening in order.
Honestly, trying to read them chronologically by story date instead of release date is a nightmare I wouldn't wish on anyone. Stick with publication order for the proper character development flow.