Now then, on to your proposed stock.
I would go with a
snowflake eel because they're inexpensive, readily available, and beginner-friendly. I say get a smaller one because you don't want a baby (too fragile), but you don't one the size of what I have (too big for that aquarium). They can growth 0.5" per month if kept well-fed; the one I have hasn't grown that much, but I have noticed a slight increase in its growth rate upon getting to eat foods other than frozen whole krill (only thing it got at the LFS). A varied diet of frozen foods is best, and these eels love to eat frozen seafood such as whole krill, squid, and octopus. These eels feed on invertebrates and have teeth that are meant for shell-cracking rather than gripping, so they sometimes can be kept with other fishes if kept well-fed; however, they may go after invertebrates even if well-fed, so be prepared to replenish your hermits on a somewhat regular basis. Be sure to provide it with plenty of caves, and also have a tight-fitting lid to prevent an escape. If you wish to test if your eel is at least somewhat community safe, then introduce a small damsel that's been quarantined and adjusted to the aquarium water; these fishes are super cheap (maybe $5 at PetCo), are colorful, and are pretty much bulletproof. They can be aggressive, so be sure to research the particular species beforehand; I found the
yellowtail damsel to be pleasantly colored (blue with a yellow tail) yet reasonably non-aggressive (bottom of the ladder in my aquarium). You're going to be at full capacity (if not over if not upgraded soon enough) between those two fishes when they're small, so adding further fishes is not recommended.
As for your invertebrates, get a mix of dwarf blue leg hermit crabs and snails; those two groups of invertebrates will help to keep the algae and detritus in check while keeping your sand bed well-stirred.
LiveAquaria.com has a pretty sweet deal on a "Build Your Own Reef Cleaner Package," and you'll spend way less than what you would at an LFS; the shipping is free, and everything has a 14 day money back guarantee. I also have some fighting conchs in my aquarium to help with the detritus and sand stirring, but they need supplemental feeding if there's not enough detritus; they are also a big help when it comes to cleaning up leftover eel food since I tend to overfeed him in order to ensure that the trigger gets some food, too.
. Help me out!! Point me!! A broken down list and tips rather than shoving me onto a article would be more helpful btw.
