Is it possible to visit it inside if there are no events in programme? If yes, is there anything to see? I was thinking about an exhibition related to Brooklyn Nets since its their home: anything like that?

I really have no clue.

Honestly I don't know. You would probably have to contact the center and find out

I've walked by several times while there was no event happening, & I've never seen anyone go in directly. There is a Starbucks right in front, & it's open on a regular schedule, but I've never tried going in the center just b/c.

I'm not sure. I've never been there when there wasn't an event.