Yes, to go to the 68th/70th floor, a ticket is needed (they'll check tickets before you're allowed in the elevator).:
If you mean the observation deck, yes
Yes
Went yesterday and they said we needed them. Luckily we booked online in advance.
you can buy in person or before
You can buy in person or beforehand
No,you can buy in person
You don't need a reservation. Maybe on the weekend? But you can walk there and buy tickets and go straight up the elevator. No wait or crowd really while we were there last week.
No, I did not need one
Thanks! Your answer is awaiting moderation.