Do you need tickets for entry to the free Millennium concerts and if so where do you procure them?

No tickets, just get yourself there (after a nice walk outside on the terrace) and enjoy the show. I've seen some wonderful performers there.

No tickets needed, the stage is outside of the main theater

No need a ticket to the millennium stage. But may have exceptions for some shows.

No need for tickets

Generally not. You can walk right in