A321 inflight entertainment (IFE)
 

Hawaiian did not order their A321s with AVOD seat back entertainment such as can be found on their A330s.

From HawaiianAirlines.com:

"Guests seated in the Main Cabin and Extra Comfort section of our A321neo aircrafts can stream inflight entertainment to their mobile devices, tablets or laptops."

Though it does not specifically state it, can it be assumed First Class customers will be offered a tablet?

The answer is apparently yes, long haul First Class includes complimentary IFE either from AVOD or tablets. From a different page on the website

This page confirms tablets will be given out in first on the A321neo: https://hawaiianair.custhelp.com/app...tail/a_id/3124

Is there going to be a charge to "stream" the new in flight entertainment on personal devices on these flights? I wonder how it will differ from the other planes where you pay for the entertainment package.

In the link provided by Kumulani, it says:

In the air, connect to "HawaiianAirWifi."
Open the Hawaiian Airlines Entertainment App and choose from movies and TV available for purchase.

So most likely, it will be pay-per-view?

The only thing that's changing about the in-flight entertainment on the 321neo is the delivery format. The pricing and packages will be the same as the A330.