If someone in the group doesn't take respecting the artifacts seriously, can we request to wait and be placed in a different group? Could their negative attitude/statements effect the whole group?

The tour guides are very nice. I would ask to be moved to a different group. Quite sure they wouldn't mind. Normally there are other groups one section behind and ahead.

No

I would just ask them to shut up or the demon downstairs could grab them and drag them down and eat their flesh.

When I was there they had a lot of groups going going one after another. I'm sure you could ask to wait for the next group.