but without seeing it, its hard to say. Not sure that the, what I call Z brick will adhere and stay on that fireplace. Tile, to me would be out of the question.

Whole brick would be my only alternative, but I would have to think it over if I could afford to loose that much space in the area. Meaning the width of the brick.

But, if the room is big, then I would just have a mason come in and brick it up and around it. There are also some very pretty rock like flagstone or something like that which could also work.

Keep trying the masons and find one that will talk to your honestly and talk pros and cons about the job.