The inverts I'm planning to get would be like a clean up crew, which, if they can be mixed, would include Cleaner Shrimp and/or tiny-to-small Hermit Crabs. The list on LiveAquaria has a nice list which includes shrimp, snails, crabs, sea slug, sea cucumber, urchins and starfish, that are pretty small. Also depending on if a reef would be included or not. The hard part is trying to figure out which ones are worth the risk or not.
For a clean up crew check out reef cleaners.org. For the ornamental stuff you can add later on based on what you need to get cleaned that isn't or just ornamental. No reason to get a sea slug, cucumber , urchin, starfish, atleast until you are way down the line