Hamilton had the option of going first or second during Quali., he chose to go second. Now that Nico has pole, he'll have first pick on race strategy.
Toto Wolff suggested during an interview with SkySportsF1 that the "offset strategy" is not very good here, and that Lewis will be disadvantaged with the #2 strategy.
I like how Mercedes is allowing them to race, but will not allow the #2 driver to take advantage of pit-stops. If you're leading the race, Mercedes will give the P1 driver the first call on w/e he needs. P2 driver can't undercut P1 in the pits, and has to overtake him on the track.