Have them recess the boxes into the brick. Before the mortar cures you should pull them all out and set them aside. This allows you to easily drill through the sheathing behind the box to run a cable to power it later. You can ten put the boxes back into the holes and use polyurethane caulk to anchor them. The front edge of the box should be flush with the face of the brick. A little proud is acceptable, but recessed is not.

HOLD IT!... so you're chiseling out a j-box-sized hole into the (hopefully) hollow-core of your CBS wall, just so the exterior box will be flush-mounted? How do you know you won't hit a center web, or TWO end webs in the block structure? Plus, every so many of the aligned vertical cavities contains a rebar, and a poured column... don't want to damage that either! =:O Generally, in a CBS home, you live with big "bumps" on your exterior walls, wherever aftermarket boxes are added, and there are no "architectural features" (wood/foam/entry foyer) to embed them in. But, assuming you've reconnoitered your structure with a drill and coat hanger... In answer to your question: NO, you can't use an INterior EMT box on the EXterior of your home, CBS or otherwise, then jury-rig it with stucco, LOL... (I'm assuming CBS = Florida or the Carribean?... ;') Besides, I don't think the Liquidtite/exterior gasketed covers will properly mate/seal with an EMT box. Oh, I know, there's a million tract homes, and under-inspected addtions out there with such "rigs", but they don't meet code either. Conversely, YES, to meet code, you must use an EXterior j-box... they come in PVC and coated metal. I'm no pro, but I've seen no prohibitions on stuccoing over... after inspection. Probably have to "rough up" the box for REAL stucco to adhere... I'm thinking there's a thinner, textured fascimile (spray? brush-on?) made for this... me, I just paint (box only), and leave it smooth. The faceplate + hinged covers I just leave gray/white/original... would only consider using spray on them. I'm not sure what code requires to connect inside and outside boxes, but I just use a 1/2" (nominal) dia. RIGID (threaded) nipple that's long enough to span the block + stucco + whatever's on the interior side. IIRC this requires a hole made w/ a 7/8" masonry hammer-bit. The metal exterior boxes are pre-threaded for such, the interior box will need a locking collar. You'll be grounded up the wazoo... esp. if you top it off with a GND wire! (optional)

Running NM from the interior of the house through the brick/stucco/mortar/concrete/volcanic pumice/whatever is fine. You'll need a box connector on the rear of the box where the NM enters. You can put a bead of silicone along the rear top of the box if you want. I'd fill the hole in the wall at the rear of the box with good old Duxseal, the same stuff you'd use on service entrance.

@gracie01 brick veneer (not structural), if old and moisture gets in, can falter and fall. It's not the brick that fails, it's the wall ties holding the brick to the backing material, either wood or metal framing or another brick or stone wythe that fails.Failed wire brick tie. In some cases, through negligence or ignorance there may not even be ties! Edinburgh Oxgangs Primary School veneer wall collapse. No ties used at all, according to a BBC investigation. Brick veneer is largely a 20th C. phenomena, with the first documented use occurring in 1899. As the metal ties rust away, support is lost and the veneer moves. In only one municipality I've built in, were longer-lived stainless ties required. Otherwise there were no requirements re ties. If the mason were supplying ties, count on the cheapest and flimsiest available. In the house we're currently living in, the masons used nails to tie the brick to the structural block. Where the back of the block is visible in the garage, around the end of each nail a quarter sized section of block has fallen off as the nail rusted. The house will be demolished by the next buyer, so there's no concern.