I have the BioCube LED 32 - my best advice is to go into it knowing the limitations of the product. Just plan on keeping low-light corals and a reasonable fish load and you will be fine. Zoas, frogspawn/hammers, bubble coral, etc. all are fine examples of corals that can work. The biggest benefit of the inTank product is that it better directs water flow over the media. Your media will likely include carbon and a chemical filtration media like chemipure blue or elite (with gfo) per your liking and tank needs. You will need biological filtration too - exactly what size will fit in the chamber I don't know. 16 is small, so it won't take much. Water changes will be your friend lol!
Most of these media options are not necessary. Live rock works wonders as a biological filter and the skimmer is your mechanical filtration. Many corals don’t require such pristine water. If you go the soft coral route or LPS route, they actually won’t do as well with little to no nutrients. I never use carbon or other filter media’s in my two nano tanks.
Dory look alike would be the yellow tail damsel. I had one with a clown in my 29, now he's in my 90. Some say they're aggressive but maybe I got lucky. For a small tank I'd just do weekly water changes, way easier than dealing with all the media. Toss in some carbon every now and then.
