As you're flying J I wouldn't worry at all about sCO vs sUA crews; they're both fine in the pointy end. As it happens it's sUA that crew the 77W and sCO crewing the 789 to HND.

As regards the pressurization, it's the 787 that has the new design (composites) that allows the greater pressurization. Though UA's 77Ws are newer delivery they're still made of metal. That said I've not noticed any real difference re jet lag; for me it's 4 days' recovery time max and less if you can be disciplined in flight and at your destination.

And with a mid afternoon arrival at NRT the Narita Express is fine for getting to central Tokyo.