I wouldn't use the 1/2 diameter in brick because there isn't enough width in any part of the brick to drill a hole that big. They are great for concrete, but with a brick you are drilling out most of the material meant to hold the screw. I would use several 1/4 diameter screws instead. Make sure you place them in the solid edges and center of the brick. Not in the hollow cells of the brick. You can also countersink the wood an inch to allow 3" of anchor into the masonry.

Yes easy. You will have to drill your 1/4 inch hole first. Personally I would not go through all the hassle of mounting the wood just to mount your tv mount. I took my 60in. Drill two 2in holes no more than 10in apart. Take a couple 1.5in tapcons put a washer with a hook on them. Screw the tap cons in tight. and that part is is done. Now use stainless wire and just tie it from left to right on the back of the tv and you can hang your tv on the front of your fireplace. then you can easily lift it off like a picture frame if you need to add a new wire. and it's flush mounted to. It looks better than hanging off with a tv mount. Those screws will not come out once in so don't worry about only using a 1.5in tapcon or your tv falling.

One of those Tapcons will hold over 2000 lbs in shear. I think you should be ok

Mounting a tv to a brick wall (back of fireplace). Without seeing it may be a bit of a weird question but. I need to mount two 4x4 boards to the back of my fireplace's brick wall. I will then attach the tv mount to the 4x4s. I plan on using Tapcon 1/2" diameter 6" screws. Would these screws being drilled 2" into the brick provide enough support in this set-up (approx. 100lb. total)?