If you could swing it I would invest in getting the glass top and just cutting it back. If your using the plastic/glass version I'm thinking of many of the morays will push the lid up if you were to go with anything that has some size to it. Morays are very strong for their size.
As far as eel types with those fish you listed that's a bit of a gamble. GDW's stay small, usually under 1' and generally will not bother fish/ invertebrates even though they are primarily fish eaters. Probably your best bet if you want to keep the fish you have listed I have 4 of them and to date have not had any problems with them eating any of my fish nor have I heard of anyone else having any issues. Could they, absolutely. It's always a bit of a gamble imo when it comes to morays. Generally speaking, the gymnothorax and muranae species are primarily fish eaters while the echidna species are either invertebrate or fish/invertebrate feeders. Snowflakes are generally considered model citizens as are the chainlinks for example, however I have seen more snowflakes and chainlinks eat the fish they swim with then what would be considered some of the more aggressive morays.
Zebras are a decent choice if you can get a small one. Usually very mild mannered and usually will not bother fish. I have 3 right now. I feed them shrimp and squid with the occasional crab treat. I have some smaller fish in my zebra tanks including hawkfish, tangs, various damsels, etc.
I would stay away from dragons unless you put them with larger fish, especially fish with some type of protection like lions and scorpions.