Marina is expecting her third child -- gender unknown -- who will be a sibling for big sisters Hali and Esmee.
Marina writes: " I would love a short, perhaps similarly 2 syllable name that is unique but pretty. I came across a name Lacie the other day for a girl which I thought was pretty and rare. I’m also very interested in sea-inspired names (like mine & Hali's) but I feel I’ve been through them all and either they are a bit too out there for me (e.g. River) or perhaps don’t go with Hali & Esmee (short, 2 syllables). I’m thinking Arlo for a boy but for some reason I’m now hearing this a bit now too (I don’t mind as much for a boy)."
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Arlo is a great choice with your girls' names and, if it feels right, go for it. One reason you may be hearing it a lot more is that it is a hot favourite at the moment, ranking at #34 having only been in the top 100 for 3 years.
For the most part, I've chosen names that are not too common but now too out-there (the elusive sweet spot) and highlighted some sea-themed names as well.
Ainara / Enara – Common in native Spain but rare in Britain, Ainara is the popular Spanish form of the Basque name Enara meaning "swallow bird".
Cleo – A sassy and bright Ancient Greek name meaning "glory, fame."
Delphi – An ancient sacred site which derives from Greek delphis "dolphin", giving a suitable 'sea' theme.
Dolcie / Dulcie – Meaning "sweet", Dulcie and Dolcie are names that date back to the Middle Ages and are in a similar vein to Lacie.
Juno – June made your list as a potential middle name, so I wanted to suggest June's namesake Juno -- Roman queen of the gods. It ranks at #485 making it 'known but not commonplace.
Lena – A flapper-style name that has plenty of style.
Meri – A sweet Finnish name meaning "sea".
Merryn – A lovely Cornish name meaning "sea-born" which is linked to a legend of a mermaid.
Mira – A Sanskrit name meaning "sea" which was borne by a 16th-century Indian princess.Mira also means "peace" in Slavic languages.
Naia – Rhyming with Maya and Kaia on your list, Naia is a Basque name meaning "wave, seafoam".
Posie – A delicate as Lacie, Posie is a sweet and unexpected floral choice.
Romy – Close to Remy on your list, Romy is a traditional nickname for Rosemary.
Beckett – A sleek and stylish surname-firstname which is easily accessible but rare in use.
Blake – A literary name with a cool sound.
Bodhi – A term of enlightenment now used as a fashionable boys' name.
Ivo – Historic Ivo has the cool sounds of Arlo but is much more unique.
Jago – A sleek and stylish Celtic form of James.
Koa – A great Hawaiian name meaning "warrior" which makes a rarer alternative to Noah.
Levi – A fashion-forward Biblical choice which sits below the top 100.
Leon – While brother Leo sits right near the top of the top 100, suave Leon is near the bottom. Just as stylish without the popularity.
Milo – A pocket-powerhouse. Milo is both friendly and sophisticated.
Zane – While Zain is an Arabic name meaning "grace, adornment, excellence", Zane is a West Country name derived from the Anglo-Saxon name Saewine meaning "friend of the sea".
I hope this has been of use. Best wishes for finding the perfect name.