I'd say 90 minutes at a minimum.
While it needs some updating, there is some good information about connecting/connection times at HNL et al
HERE.
I'm really not sure why HA would be doing this; iirc, the responsibility for making sure the pax gets the luggage falls to the last carrier on the itin. Why wouldn't they want to shed that responsibility to UA? Is it possible that it is United who has decided it won't accept such bags?