Is a structural screw best for this or a lag bolt?
Looking for a ~6.5" fastener that penetrates different materials and can handle a dynamic load (a pull down TV mount with a static weight of ~100lbs). Fastener would penetrate: 3" of red brick, 1.25" of mortar / air gaps (pockets of mortar behind brick), 5/8" of drywall, and 1.5" of penetration into the stud.
Details - Hanging a TV mount that you can pull down (mantelmount) to eye level on our brick wall. Brick wall is a facade wall that uses full size red bricks. The last homeowner removed a few bricks in the center of wall to add an outlet so I am able to scope inside to see roughly where: i) the studs are; ii) the framed out hollow area that houses the enclosed gas insert; iii) and the location of the chimney pipe that vents outside.
My initial plan was to scope/drill around masonry to find dead center of studs, then use a lag bolt or a GRK 7" structural screw. Should I add a steel pipe to encase the fastener? Benefits of a steel pipe - no compression on the facade brick wall, pulling down on the TV wouldn't "saw the brick", and it would prevent the fastener from bending if there happens to be a 1.25" of air gap.
Am I thinking about this right or am I way off the mark on this one??