There are some still but I think fewer than there used to be. There is no food service currently, so you can't take a break by going to the cafeteria. Free wheelchair rentals are still available, if your mother would be willing to use one. Chicago is supposed to be fully reopened on June 11. I expect full services at museums to be restored soon thereafter, assuming they can rehire staff that were furloughed.

Not certain, I would check the museum website for more details.

Why??? Are you planning to bring a gun?

We interacted with several staff members during our visit and had no issues. Everyone was friendly and courteous. Our questions were answered thoughtfully and we were provided accurate directions when we asked.

Google “Art institute of Chicago annual membership.” Once on their website you will see different options for membership. Or you can also go there and buy it directly. If you decide to go there to buy directly, it’s best to do it during weekdays. They’re less busy. However, if you go on a weekend or holidays give extra time for the crowd.

No idea. Contact museum.

Not sure about that. Our tickets were not for a specific date. You should call them but most likely you’re fine as long as the ticket has not been used for entry on another day.

Didn't seem like, for me.

You could purchase that at the place you pay for admissions.