Not quite all accurate.
Out of state and coming to Hawaii you have to register firearm within 5 days of what arrives last (you or the gun). Registration requires you to complete forms regarding any criminal conviction for crimes of violence, any mental health issues, drug use, medical marijuana card holder, or anything that disqualifies you from owning or possessing firearms will cause issues. The Records section does a NICS check and warrant check which is typically quick, unless you have one. The firearm is not held unless you don’t qualify or if it is an “assault pistol”. There’s no “approved” pistol list. In 2016, Hawaii mandated person registering a firearm has to be registered in the “rapback” system which costs $42 (this is for out-of-state residents too).
The only thing you are required to register is the firearm, don’t bring mags or ammo when registering (leave them in your room).
Transporting requires the firearm to be unloaded, in a rigid container and only to-from, no side trips.
Once the firearm is registered, it is considered registered in the state and do not need to be registered every time you come to visit. Also, once you pay for the “rapback” you don’t have to do it again for another firearm.
Hope it’s more clear.