Increasing Heath Depth for Gas Insert Conversion

[Buck 22]

I have a brick wood fireplace. Plan to convert to gas . I want to build out brick hearth and do a tile surround. Presently brick is flush with wallboard. Was considering adding a layer of brick to extend fireplace opening from wall approx 4 inches followed by framing and covering framing with cement board and then tile surround. Seeking advice and recommendations regarding this project. Any concerns with this approach for bumping out hearth for tile surround? Photo of current fireplace is attached.

 

[DAKSY]

How far do you need to move to fit a gas insert? Sounds like you talking about moving the facing almost 8”.