Hi, these are all great eels, they are all hardy. I would go with a snowflake they are great looking, stay small, and aren't that aggressive. But if you want some info heres some info I know. Snowflake eels are small in size (compared to other eels), it is easily compatible with other fish as long as the fish are not small enough to get eaten. Snowflake eels get to about 30 in. in length.
The zebra moray is my favorite and i'm going to add one in my 220 when I get it.
Lets back to the eel, Zebra morays are a little slower than other eels, it adapts to captivity realy well, and they have been known to live up to 20 YEARS!
Chainlink morays are nice little eels, they get about 24 in. in length, and are just a little meaner than snowflakes, but are peaceful. It's up to you really. But what size tank would it be going in? The 55 or the 250 gallon? If it would be the 55 gallon, I would go with the snowflake or chainlink. If it's the 250, i'd go with these three eels, you listed. There are other eels that you can get instead, but may be meaner, or may get a lot bigger. I would go with these three great eels.