Use RedHead Sleeve anchors, readily available at Home Depot. You could hang 10 tvs off those things, it's not going anywhere. I can't remember the size bolt I used to get, but the nut on the sleeve is 1/2".
If you want to conceal the wire, take a masonry bit approximately the same size as the mortar spacing and drill a series of holes around an individual brick that will be behind the TV. Behind that brick is a regular wall, pop a hole through the drywall and fish your wire accordingly. (In this scenario, cut the hole in the brick closest to the top of the tv)
IF you don't have an attic, then you're going to have to go sideways. Your fireplace probably has some quarter round molding where the brick meets the drywall, peel it off, cut a hole in the drywall at the level where you'll remove the brick, use a long wood bit with extension(s) and drill through the studs. (IN this scenario remove your brick at the furthest point (left or right) so you only have fish sideways maybe one stud bay.
When you remove the brick, cover everything with tarps...That brick dust gets everywhere...When you have all of your holes drilled around the brick, start smacking it with a cold chisel and a hammer..Remove the brick and you have enough room to install a gang box for power.
You'll obviously need an HDMI extender....Don't bother to try and run an HDMI in there, it's too much of a pain in the butt.