The bulkhead definately has more leg room so you should be quite comfortable. On all of my flights more than one section of the first bulkhead was filled with families with small children who were up and about throughout most of the flight. I did notice that the children liked to go over to the bulkhead to look out the windows. On the JFK flight the majority of families seemed to be in the first Y section anyway. However as there were 80 people total (all classes) on the flight you could pretty much move wherever you desired (within Y, of course).

As for seat selection...it is hit or miss with the U.S. reservations office (in Y) as they will actually only reserve (according to the U.S. Website and who you speak with) any seats in advance for two people travelling together (i.e. family) which I was, but had to make an extra effort to get seats in advance. I suppose the single traveller is on their own. Based upon your experience I am assuming this is not the case globally but the NY route was still new when I flew it so perhaps they were working out the kinks.

But the inflight service was superb and the 500 a great aircraft. Have a great flight!