I voted for Sirene and Seaport.
That's a great combination, also reminds me of Sirens of the sea, like mermaids... and also Sailor Moon's name Serena...and the Moon & the Sea are often depicted together in folklore.
I personally like
Seaport, and also
Coral--I think Coral is the most unique name on the list.
OP: I love the amount of thought & research you have put into this ( I did the same for my town Lantern, Mayor Misuko!

) and I look forward to seeing how your town develops.
I LOVE the name
Ryoko, and it's meaning. It would be the perfect choice depending on the personality of the Mayor.
Ryoko sounds like a heroic name, a beautiful & Lionhearted person with lots of energy & spirit!

They could be a sweet & good person, but also capable of leading an army or being something like the head of Griffindor! I don't know why, but this name stirs up so many positive images for me.
After I post this I'm going to look it up, because I wouldn't be surprised if it's the name of a famous Japanese leader or movie star. A V.I.P. for sure!
If you want a more passive & soft name... I think
Misaki really stands out as a name for a beauty. Even before reading the meaning I am reminded of flowers.
Finally
Misora is equally as beautiful as Misaki--but a little softer still & the rounder sounds give it a mysterious tone. As it has a meaning relating to the sky, so again related to the moon & therefore linked with the sea...
I hope this helps. I think you should choose by both popularity of votes & the various answers in the comments. If one is only a few votes ahead of one that many liked in the comments, or you personally like better--don't be restricted by the votes or opinions of others--in the end
you want to be happy with it.
- - - Post Merge - - -
A quick perusal of wikipedia shows I was correct about Ryoko! A long list of actresses & a politician who won Olympic medals!!!