Tickets are required for the African-Amercan museum, but they are free.
No, you need to get ahead of time when they open the tickets for 3 months ahead or you can try and get same day entry based on the amount of visitors that day.
Tickets? All Smithsonian museums and zoo are free. There might be very special events happening in each that very rarely may need a ticket which would be sold next to them.
You need to have printed ticket so I do not think calling will work
Thanks! Your answer is awaiting moderation.