I've been trying to create a story that isn't all that cliche and I found not that many books have been made with the plot surrounding mermaids. However the more I thought about it the fewer mermaids seemed to fit in with the story. So I started looking at Nereids which is a sea Nymph which worked a little bit better considering I'm trying to factor in the fact my main character has a humanoid appearance and doesn't grow legs magically in the water at all (she does need a good soak every once and a while to reconnect with the sea) But now I'm thinking Nereids arent the way to go either since they don't particularly have the magical properties of controlling water and they may be a little too embedded into greek lore. So I'm thinking of a siren/Nereid hybrid of having a humanoid appearance, power over water, and control over people with their voice.
My story also goes off on the fact that my main character was thrown overboard because of the superstition that women bring bad luck when on ships.
I'm also maybe trying to incorporate the sea itself. I know in Nereid Lore the woman would ride on dolphins to travel and I was thinking a hippocampus of sorts but now I may be delving too much into Greek lore and throwing the idea a little too out there. I could use animals native to the area, seals, turtles, hell even the dolphins. But what my main character would be doing in the sea I'm not too sure of yet. I don't even want to touch the concept of a little mermaid idea or even really delve too deep into an underwater world.
Just some help with maybe cementing ideas and getting a grip on not being so wishy-washy. Is this concept too far-fetched?