I think a lion is perfect companion for an eel. Very rarely, do they eat hermits and snails. A 50 gallon may be to small for some species of lion.
Wrasses, on the otherhand, are really a crap shoot. Some will hunt down inverts relentlessly, others will eat them when convenient, and some leave them alone all together. Wrasses also have a tendancy to lie in the sandbed at night making them a target for an opportunistic eel. I've lost 2 wrasses to my Snowflake Eel. To be a Wrasse in my tank, you need to be on your toes.
You could do a plaktonic trigger *Size considerations, Filefish, Damsels, Reef Wrasses, etc.