I know you can't have magazine fed pistols or something but could it have a 10 round fixed magazine? I am wondering if I could have a AR with a short barrel or something but please let me know if there is any way. Thank you.
As for a short-barreled rifle, those are forbidden. Unless you have a military or law enforcement exemption, all NFA items are forbidden here.
The rules and forms have changed since this horse was last beaten to death. There was a process whereby you bought the receiver from an FFL/Gun Shop, and they would check the box "Handgun". If they checked anything else, it could not legally be configured as a pistol.
So, if you already bought outside the state and the 4473 didn't classify it as a handgun, there's no way to undo that. It's ineligible to be a pistol.
Let's assume you are starting from square one. Get a handgun permit from the PD. Use that to purchase an AR receiver. By presenting the seller your handgun permit, they should automatically check off the Handgun box on the 4473. Make sure they do before you sign it.
Now you have a receiver that is technically and legally a pistol, you need to register it that way. Then the real fun starts.
You have to decide which way you want the pistol to be crippled. You can either (1) permanently attach a 10 round mag to the receiver (epoxy seems to be the favorite method accepted by HPD), or (2) you can not install a gas operating system by leaving off the gas block, not drilling the gas port on the barrel, and of course the gas tube (no gas block, no way to install the tube). Either method should avoid it being classified an Assault Pistol, since #1 eliminates the removable mag factor, and #2 eliminates the semi-automatic action factor.
Once you pass that hurdle, the rest is just doing the build. When you first register it before starting the build, you'll be asked to bring it back to the firearm section for inspection after it's finished, so they can see if you crippled it to their liking.
So, the short answer is "Yes, you can have an AR pistol here if you satisfy all the legalities, permitting and registration so it's treated as a handgun from the very start."
The real question is, do you really want to go through all of that? I guess it depends on how much you want an AR pistol that's functionally castrated.
Once it's built and registered, you can't put a rifle stock on it without also attaching a 16" or longer barreled upper. Seems like too much work to reconfigure it with a buffer tube for an AR stock after having a short buffer tube for a pistol. I'm not sure what the current status is with the state's pistol braces rules. I think the feds have said they are legal now, but I'm not sure if Hawaii is following their decision, too, or if there's still a lawsuit going on.
Just more legislative mines to avoid when trying to adhere to their ridiculous laws and restrictions.