The easiest way to answer this is to find the name origins, and then see if they appear to follow a specific theme. (I used Bulbapedia for most of this.)
Vaniville Town: Quite plainly based on vanilla, a type of flavouring taken from the fruit of a vanilla orchid.
Aquacorde Town: According to Bulbapedia this town's name come from words that have to do with water in each translation, mainly meisui (mineral water) in Japanese, aqua in English, and Aquarelle (watercolour) in French and German.
Santalune City: Takes its name from Santalum (a genus of woody flowering plants) and Indian sandalwood.
Lumiose City: This city's name is taken from Paris' nickname, La Ville-Lumière, and the word grandiose, according to Bulbapedia.
Camphrier Town: Literally the French word camphrier, which means camphor tree/camphorwood.
Cyllage City: According to Bulbapedia it likely takes its name from the French word sillage (how long a perfume's scent lingers in the air) and possibly sage plants.
Ambrette Town: Taken directly from the ambrette flower. It's Japanese name, Kōjin Town, comes from the Japanese word for red ginseng.
Geosenge Town: Name derived from the prefix geo- and Stonehenge, and maybe ginseng (but unlikely). It's Japanese name includes the word sekitai, meaning stone moss.
Shalour City: From the sacred shala tree.
Coumarine City: Probably from the French word coumarou, their word for tonka beans, as well as "marine."
Laverre City: From the word lavender — a colour, scent, and plant.
Dendemille Town: Takes its name (again!) from a French word, this time dent-de-lion, meaning dandelion, as well as the English word windmill.
Anistar City: A mix-and-mash of star anise, a tree with star-shaped fruit.
Couriway Town: Takes its name from caraway, a part of the carrot family. It's Japanese name comes from renri-sō, meaning sweet peas.
Snowbelle City: Pretty obviously a portmanteu of snowbell and belle.
Kiloude City: According to Bulbapedia, this city takes it's name from "agilawood and oud, alternative names to agarwood."
CONCLUSION: The names of Kalos locales do follow a theme: almost every city and town in Kalos has a plant somewhere in its etymology.
Iki Town: Iki is a Hawaiian word that means "little."
Hau'oli City: Hau'oli is a Hawaiian word that means "happy."
Heahea City: Heahea is a Hawaiian word that means "warm welcome."
Paniola Town: Paniola is the Hawaiian word for "cowboy." In every other translation of the game the town's name includes the word ohana, which means "family."
Konikoni City: Konikoni is the Hawaiian word for "passion."
Malie City: Mālie is the Hawaiian word for "calm" or "serene."
Tapu Village: From tapu, Hawaiian guardian deities (and, obviously, Tapu Koko and friends).
Po Town: Pō is the Hawaiian word for "night" — fitting, seeing as it is Team Skull's base.
Seafolk Village: Just the English word "seafolk."
CONCLUSION: Alola's cities and towns don't appear to follow a strict pattern like Kalos' did. Generally they are Hawaiian adjectives, with a good amount of them being emotions or states of being. However, I think the names for Alolan towns were chosen to describe the town, rather then follow a specific theme. For example, Paniola Town is has a wild west appearance and is surrounded by ranches, so the word "cowboy" is appropriate.
EDIT:
This is strange, Google Translate is giving me different results for some of the words than Bulbapedia says… like, paniola is apparently "panic," heahea is "open," iki means "nothing," and konikoni means "console." Of course Google Translate isn't the most accurate translator, and I'm don't speak Hawaiian, so I'm not sure which translations are the correct ones. If these ones are correct, however, then it appears that Alola's towns do have a common theme, that theme being emotions or feelings.
I hope this answered your question adequately!
