I would use a grinder to put rebar down over the gap, set into the bricks, put cement board on top of that which has a 1/2" overhang onto the brick. I am extra and would do a rebar every brick across the short side. From there you can built a mold to pour a rebar and concrete slab with a 2" overhang, or no overhang if your rain cap can accommodate the tile extensions. The overhang will help to protect the mortar joints of the brick, so if your cap has less drip edge, I would just pour with the overhang. You do want to make sure the concrete is shaped to allow for water runoff, water sitting on the crown will fuck shit up faster if it sits. Use some foam seal around the tiles to give some relief for expansion and contraction. Seal over the foam with an exterior polyurethane sealant so water will have a harder time acting on the joint between the tile and the concrete.
If you elect to have the tiles with their own individual rain caps, I would suggest adding a sand cap over the concrete to act as a sacrificial wash. You'll want to slip a tuck pointing trowel up against the tile to give some expansion room. Seal that wash to the tile with polyurethane as well. You don't need more than an inch thickness, tapering to 1/2" at the edge. You will have to replace/patch that sand cap every so often, so make sure to check on it. Most of the time you just need to patch it with the leftover sand cap thinned out and applied with a brush, but you can use mortar as well.