I highly recommend using one of the alternatives (HHG or bringing with you on the plane) which doesn't involve you "acquiring" a firearm in Hawaii. If you brought them on the plane, or in your household goods, no proof of training is needed. You just take the guns to HPD within 72 hours and register them. Piece of cake. You just walk up to the window and say, "I brought these with me from out of state, and I need to register them. They write down some serial numbers, print you like a perp, do a background check, and then let you go on your merry way with your guns because, surprise, a legal gun owner isn't a felon.
The other method is where you have guns shipped to an FFL, which means you're "acquiring" them. That requires formal training and a permit. Once approved for the permit, you have to endure the ludicrous two week waiting period, then you get your permit. Then you go pick up your permit and jump throught the BS hoops that Alex detailed. I haven't purchased any guns out here, and I intend to delay that for as long as I possibly can, for all the reasons Alex listed. Good luck!