you may want to call in a contractor and have them “bid” the job and just ask them how they plan do it…
but if I did it myself, I would probably cover the brick facing with 1/4″ concrete wall board, installed with “rock on” screws for a nice flat surface, apply the mastic (ceramic tile adhesive) then set the tiles, following with the grout…
I would make sure the heat generated at the fireplace would not interfere with the adhesive or grout first
