Am I correct that the first "week" will be 8 days so that the Opening Day NYY game is included rather than ignored?

Yes, Sunday nights game will count. It is the first game of week #1 and all lineups are due before 8:00 PM ET on Sunday. Game time is at 8:05 PM ET.
If ever in doubt of the lineup deadline, go to the League "Calendar" on our CBS League Home.

Also, There will be NO waiver claims this Sunday, April 4th. Your last chance to turn in a pre-season claim is Saturday, April 3rd, 11:59 PM ET.