I've kept snowflakes in a reef tank before. Fish that size should be fine with the eel, but there are a few things to keep in mind before getting an eel.
Do not get more than one in a 75g.
Eels produce an insane amount of waste, and will greatly increase the bioload on your tank. Make sure your filtration (skimmer, chemical, etc) is up to par.
The shrimp should be removed from the tank, as they will most likely become lunch and/or playthings. In addition, my snowflake would occasionally go after snails and hermits, which caused me to need to replace my cleaning crew more frequently.
Having a top on the tank is a good idea, they can and will jump if they're not happy (and the possibility is there even if they are happy). If an eel does jump, rinse it and place it back in the tank quickly. A seemingly dead eel will often survive (sometimes for hours) outside of the tank.
Eels do not need to be fed daily, and doing so will pollute your tank and can shorten the life of the eel. Once or twice a week is sufficient, and feeding should be done with a feeding stick (Do not hand feed. It looks cool, but an eel bite will hurt and can cause serious infection). Due to poor eyesight, you'll need to put food (krill and silversides are excellent) in front of his hiding spot and let him grab it.
Eels require plenty of hiding spots in the tank, and if your rock work doesn't provide this, you'll want to rearrange or add PVC tubes for the eel to hide in.
If you're still interested in the snowflake after taking all of this into consideration, spend the $10 on this book. It will answer most of your questions.
http://www.amazon.com/dp/079380566X/?tag=reefs04-20
Hope this helps.