Didn't have the ability to type a lot so now I do.
1) How long will you live here for?
All guns in HI must be registered with the police (HPD). There is no way to un-register them if you leave the state. Also u have X days to notify HPD if you are "permanently" leaving the state by which guns are leaving.
With the above being said, I would only bring the minimal amount of guns needed if you will be here for less than 5 years. And securely store the rest on the mainland.
2) Another benefit to buying the guns on the mainland is for handguns to be purchased in HI, you have to take a Hawaii handgun safety class. Then add in the 2 week wait per handgun that I mentioned above. So if you can afford them, buy them on the mainland. Unless you're coming from CA that has a handgun registry and those you want are not on the approved list. What also ties in is #1 and how long u gonna be here.
Guns in HI are typically more expensive than on the mainland. And selection isn't usually as good. VP9 should be on the shelf here, but the others may not. It's hit or miss, but stores can special order.
There is no class required for a rifle (long gun) or shotgun. But you still need a permit to buy them from HPD. Unlike handguns that are serial number specific, the long gun/shotgun permits to buy are good for 1 year. But you still have to register them.
Definitely google HRS134 and read most of it. It's in legalese, so for me, I had to read each sentence like 5 times to understand it. You can also check out the legal section if you have questions or any other section on this forum.