I'd recomend using a line-pin to chisle out the brick. Cutting the mortar is easier until you nick a brick next to the one your taking out, sometimes it's better to take a little more time rather than risk other bricks around it. I'd also be careful when taking out the mortar joint if the brick is particularily brittle, it can leave razor-sharp edges and has a greater chance of chipping. I've found chisles do work well but I've had much better success with a line-pin, it gives an even smaller point of contact when removing a mortar joint. As far as matching & replacing the brick that depends on how obvious the spot is. Assuming your taking a brick out from another location you could "switch the two. A nice tuk-pointing job and nobody would ever be able to tell the difference.