ANA is and always has been the global launch customer of the 787-3. CO was the first US customer to order the 787-8, and then convert some to the 787-9. NW ordered 787-9's. Both CO and NW begin taking delivery in 2009, so I'm not sure if any dates have been set to determine which is the US launch customer, and given the delays at Boeing those dates could easily slip..again...
The dates will certainly slip, now because of the strike more than anything else.
And NW will be the first US-based airline to take delivery, just after ANA does. DL/NW are going to keep the delivery schedule for the 787s as is; they haven't announced any plans to defer or otherwise delay taking delivery of those planes. CO did order before NW but they ordered for later delivery dates, and they agreed with Boeing to delay slightly more (announced in today's call), though it is unclear if that is a CO-based deferment or a Boeing-based delay.