Yes, it's possible.
Yes!
If you want to visit several museums and attrzctions you might want to consider a New York Pass. (Newyorkpass.com). Easy access to a lot of known and unknown attrzctions. Mostly no reservationd necessary.
Yes, near the entrance
yes , maybe you need some more time , but yes !
Yes, enter the building and turn right
Yes you can
Yes. Just walk right up to the information desk near the entrance.
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