Wow!! The TV series is almost like an advert for Hawaii. They do show a lot of shots of the area which are very highly coloured. It looks so appealing so we may well be visiting some time.
I love folk music but rarely hear Hawaiian based music over here. Other than a sound which seems close on film .... Moana!!
Doesn't strike me as an island that might have a great deal of Hi-Fi retailers so I guess you might well be buying a lot of gear from abroad.
Haven't found a dealer for HD600/650/700/800 or even DT-770,,880, 990 or higher up. about the best I can do locally is best buy which has B&O, HD-5xx senns, mid level sony and the normal beats & bose.
Many years ago there used to be a few decent audio stores that carried McIntosh, Mark Levinson, and other upscale gear but all have closed up over 10-15 years ago and is one reason I haven't sold my old gear since replacing them would be really difficult and also because the old gear is quite good even with all the advancements in tech. A good example is the NAD 3020 integrated amp that I got in 1983 (paid about $85 IIRC at a store going out of business, also got a Stax SRD-34 for $56 or something around there), its still works and not many $1k integrated amps that I've tried over the years have bettered it, another is the Citation XX, its still one of the best amps I've ever heard and granted it was not cheap back then but I got it used for $1000 since the person really needed the money.
Hawaiian music is great with the HD-650 since most of it is acoustic, my favorite artist are Iz, Kealii Reichel, Na Leo, Kalapana, Beamer Brothers, Brothers Cazimero, and Cecilio & Kapono.