you will be fine. I have a smaller tank with fish including..
Yellow tang
half black angel
pearl butterfly
scooter blennie
green mandarin
antannata lionfish
'FW' snowflake eel (not truly a FW fish, but sold that way when young in many pet shops)
'SW' snowflake eel
Humu Picasso trigger
Green spotted puffer
2 sea stars
...i think that is it. But they all get along fine. if you want to see for yourself, check out my vids
www.youtube.com/earthling1984
I would think 2 small young eels would get along better.
This is probably true. And their are some species of eel actually that you should only have ONE in the tank. Snowflakes, however, are pretty peaceful and provided they each have their own 'home' in the tank, they will co-exist just fine.
My 2 eels are actually vastly different in size. One is over 17" the other is about 8". But this causes no problems. Actually I've witnessed some funny behavior(both in my eels and my newt/salamander)... Where my smaller eel/newt went right up to the larger eel/salamander and put their noses to each other. Basically walking up and saying, "yea i'm a badass, i may be smaller but i ain't scared of u". At least that's the words I give it ;o. But each time this happens they just have a few second stair down then leave.
My larger "FW" snowflake eel(the FW eels are also sometimes called snowflake eels) saved my smaller snowflake once. I doubt the smaller snowflake was in to much trouble, but... I threw in a fairly large crayfish for my larger eel to eat, he didn't come out and eat it right away through. My smaller eel decided he wanted to try to eat the huge crayfish. He was picking and it and fighting with it. I was kinda scared the crayfish might get a nice pinch on him. After about 15seconds of the small eel and crayfish fighting, the larger eel shot out of his cave to the top of the tank and quick dived straight onto the crayfish(kinda like a hawk ;o)... Maybe he just wanted the food, but it was pretty cool to see

... plus, another reason I was thinking he was 'helping' was because the smaller eel and crayfish were pretty wrapped up, it would be hard to bite the crayfish without also biting the little eel, but the big eel dived down only grabbing the crayfish and biting the crayfish in half(usually he swallows the whole thing, but this one was extra large). He left the head end and the smaller eel, puffer, and trigger fish shared it.