Are masks required in the mall?

Yes

Yes, while inside of the various stores. While outside, you don't need them if you can social distance effectively, which is most of the time.

I would just wear masks everywhere as if it was the beginning of the pandemic. It's not about us anymore it's about everyone. Let's all wear masks to help discourage the spreading of covid-19.

Very likely

Some stores require them and some don't. Marshall's will actually provide you with one. Not sure about the other's.

Yes, while in stores. If its busy, even though outdoors, I would wear one as well. If you can maintain an acceptable distance from others while walking around or to different stores masks are not required since it is an open air shopping center