First Post, so apologies if I unknowingly trespass any forum rules or mention things that have been discussed elsewhere.
It looks like you have a running start, I like what you have so far!
You mention that the White Court trying to establish itself as well as the strong Asian influences on the islands. Have you thought about including the Jade Court at all in the power struggle? We have very (very) little to go on for them canonically, but I'm sure there are people on the forums who have ideas about how to include them in the game (my GM has made stats for them in our current game, as well). The Jade Court could replace the White Court as a power group on your city sheet, or could even be competing with the White Court about who gets to control the island.
When thinking about ley lines, why not have a fire ley line of epic power running through all the islands? It is strongest on the big island, where it intercepts the active volcanoes, and slowly declines in strength as it runs its course through the older, dormant islands. Similarly, the place where the new island is being formed (underwater volcano gradually building up from the ocean floor) is a nexus of overwhelming magical power, given that it is literally the birth spot of a new landmass. Tapping into that much energy through so much ocean water may prove problematic, however . . .
The land and ocean fae courts sound great, and could also reflect the fact that summer and winter have very little interest in the islands - with a tropical climate and very little procession of the seasons, there is little to fight over. Alternatively, summer holds almost eternal sway there, but by ancient precedent is split into Land and Ocean and locked into eternal enmity with itself. The Land Court might be based on the big island, while the Ocean court has coral palaces among the reefs of the many islands, and their biggest one is located on the most recent island to have been eroded away by the sea.
Given that you are basing the game in Honolulu, Punahou should definitely be a location. Since our current president is an alumnus, and it has the (deserved) reputation for being a rich private school, it lends itself to hiding all manner of supernatural shenanigans and powerful cabals (think Sunnydale in paradise).
Sealife Park is another one I'd include, although I'm not sure how. Maybe as a place of power for the Ocean Court, a kind of redoubt for their activities on land? You could have a sorceror(s) intent on using dolphins and other sea creatures for their totemic significane, a la "Welcome to the Jungle".
You already listed the Polynesian Cultural Center, and that it is ANG (a great idea!). What about the BYU campus? How much does the LDS church know about the supernatural? They are certainly interested in changing the status quo, inasmuch as they have a prosletyzing mission, so they deserve mention on the city sheet. Do they have a group similar to the Knights of the Cross, to combat the darkness? Do they take a more neutral stance? What about the students they have from around the world, bringing with them a mixing pot of different cultures, beliefs, and supernatural creepy crawlies. What problems might that cause for your intrepid player characters?
MCBH (the Marine Corp base in Kaneohe Bay) is probably worth a mention, if only for the interesting set of challenges it could offer if it became the location of an investigation for your characters. For the more paranoid-minded, it provides an opportunity to house government experiments on the supernatural/units with a supernatural bent. As a purely mundane location, however, it offers plenty of room for interesting interactions, especially if one of your characters has ties to it.
Honolulu has a Chinatown, and with it the chance to throw Chinese mythology into your game. It could also be a base for any Jade Court presence. If you wanted to flip the ethnocentricity around, however, you could have Chinatown be the center of the only organized and clued-in resistance to the supernatural world, thanks to Chinese knowledge of the supernatural world. They fill the function of vanilla mortals' best defense against the darkness, but their activities are usually misinterpreted by the rest of the city as ridiculous superstition.
I'll ask my girlfriend if she has any thoughts (she was born and raised in Kaneohe Bay) when she wakes up, until then I hope something I wrote helps!
