Originally Posted by
msb0b
IIRC you can only exchange for Japan Rail Pass at the green window after the travel center has closed at 1900 or so. Same goes for the Suica + N'EX so you are not going to save time by to get the Suica + N'EX in lieu of the Rail Pass.
Since OP can use the rail pass for both ways on the N'EX and shinkansen, it's worth it. Additionally, OP indicated he values the convenience of the pass.
For 5 adults + 2 toddlers/infants, I think taxi will be preferable, especially if you can get a minivan. What I would do is to prioritize traveling on JR (and use the pass), and use taxi when there's no JR station near the destination.
No, you can buy the Suica/NEX at the regular manual ticket sales to the right of the gate. The only place that you cannot is at the machines. Before the renovation they had a special line marked Suica/NEX at the "travel center" and it never seemed to be busy there. Now it's one large line and tourists will gladly spend 30+ minutes doing their planning in front of a clerk.
Once when arriving downstairs with no chance to catch train and 30 min to spare I got into the line with 4 people and 3 clerks working. I was in no rush so figured that I would it there and the line was short....... I was close to not getting the next train. Lately, I have seen 30-40 people in line spilling into the hallway. The Japanese would never say "hurry up there is a huge line and you have been here for 15 minutes now asking inane questions. Please take the next NEX and figure out your trip later".