In the order that I came up with them:
Aurelie Moonsong (female Midlander)
"Aurelie" was just a name I had in mind as something that would be cool to use for a character sometime. With more lore-knowledge it probably should be an Elezen name, but I'm going with the excuse that she's Gridanian and there's got to be some degree of crossover with naming ideas.
I think I just started throwing different words together to come up with a surname, but I'd very nearly settled on "Riversong" until I realised it would be taken as a Doctor Who reference. The actual intent was referencing a few different overlapping-in-my-mind things together, but most linkably the song "When the River Meets the Sea" and the closing poem of Alice Through the Looking-Glass.
(I had no idea the Moon would actually be somewhat important as a plot element, but in the end it's been a neat coincidence of Dalamud and summoner's association with Bahamut.)
Brynwyda Tidesong (female Sea Wolf)
Far too much time was spent re-re-reading the Roegadyn name dictionary trying to find a name that sounded nice, had a good meaning and didn't look dauntingly unpronouncable. Starting with the relatively limited choice for female name-endings, I picked "-wyda" (willow) as an association to her tank role via the Bole card.
In the end, her name means Spring Willow and I'm happy with that. No desire to go through the process again to work out her actual surname.
As with Moonsong, Tidesong started with throwing words together - loosely on a sea theme this time. I did want to find something else so they wouldn't have matching names, but I kept coming back to how those sounded together and decided to go with it. Moon and Tide. It seemed appropriate.
Sylviel Terrechant (male Duskwight)
I just ended up browsing NPC names this time, by looking up the NPC lists on Garland Tools in locations where there would be lots of Elezen. I wanted something that wasn't too long or reliant on French pronounciation (because I'm sure I'd mispronounce it), and preferably not found in the character creator. "Sylviel" ticked all those boxes.
And surnames - there was a pattern for them now. So "Earthsong" for Duskwights' links to caves, and then I thought I should maybe translate that into French (and hope I didn't mangle it)...
...and of all the luck, Terrechant is an actual Duskwight surname in the generator.
Haru Kazeuta (male Raen)
A race that uses real-world names? So much easier. Went browsing through this list for ideas. Haru has a few different meanings including "light", and I liked the sound of it.
Surname "Windsong" (for an easy-going 'travelling for fun' character) again possibly-mangled though online translation, and with no lore excuses this time. Hopefully the Japanese players aren't looking at it and thinking "yeah, you must a clueless English speaker who doesn't know how apply Japanese grammar to that"....