Any evidence that suggests Fed headquarters might be on Bajor or DS9? I don't remember seeing any hints about that, but have seen it suggested it might be.
The only ‘evidence’ is a uniform and a communicator that vaguely resemble the Bajoran uniform and symbol from DS9. It’s most likely just a coincidence, and Federation headquarters has nothing to do with Bajor or DS9. But I’ll be happy to be proven wrong.