Yes, I went on 10/15 and I was able to use the restroom without any issues. You just need a mask.
Most of the bathrooms are open, but note that the main visitor center building is closed, including the restrooms there. If you are at that building, diagonally across from it is a small gift shop. While the gift shop is closed, it's bathrooms have outdoor access that are open.
Yes, mask up!
Yes
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