Great circle from the west coast to Hawaii goes north of the 180 minute ETOPS no go hole in the Pacific. IAH to Auckland goes right through it. Unless you have 300 minute ETOPS, you have to do a big detour around the hole.

The 787 should easily do LAX to Auckland, or at least as good as the 777.

Boeing promised 330 ETOPS, an didn't deliver. I don't believe any of UAL's (either black or blue team) 777's have this either. Some 777's do, with certain versions of GE engines.