Amateur newbie question

Long story short, we had a faux stone fireplace surround installed a couple of years ago. The stone on the hearth (pictured) started coming off within six months and the rest has been gradually coming loose. I finally got tired of wondering when the avalanche would occur and pulled all the stone down and decided to redo it myself.

I have the lath up and was about to install it around the hearth, but realized that the concrete board was covering brick, so I can't drill through it to attach the lath. My plan was to apply a scratch coat (which was NOT done before) and then mortar the stones to that.

Is it okay to do that in this small area without lath? Is there some other product I should use for durability? They seem to have glued some of the stones, which are the ones that were quite difficult to remove (so I left the others). Should I try to remove the concrete board and mortar the stones directly? What are my best options here?

Thanks!

Long story short, we had a faux stone fireplace surround installed a couple of years ago. The stone on the hearth (pictured) started coming off within six months and the rest has been gradually coming loose. I finally got tired of wondering when the avalanche would occur and pulled all the stone down and decided to redo it myself.

I have the lath up and was about to install it around the hearth, but realized that the concrete board was covering brick, so I can't drill through it to attach the lath. My plan was to apply a scratch coat (which was NOT done before) and then mortar the stones to that.

Is it okay to do that in this small area without lath? Is there some other product I should use for durability? They seem to have glued some of the stones, which are the ones that were quite difficult to remove (so I left the others). Should I try to remove the concrete board and mortar the stones directly? What are my best options here?

Thanks!