We have an 1840s brick rowhouse with a recently exposed brick wall that adjoins the kitchen on the first floor. This is an exterior wall constructed of 2 courses of brick. On the interior, a section of one course has been removed so that rectangular metal duct could be run from the heating vent on the first floor up to second floor.

Due to other HVAC changes we've made, we are going to remove the duct from this wall and have the missing brickwork replaced. However, I realized this would be the perfect location for the switches that will control some of the lighting in our almost renovated kitchen.

My plan is to have the mason fill in the brick up to and around the switch box, and then cover the channel the wires are in with either brick or perhaps a nice trim board if necessary.

Is this a good idea? Are there any code issues involved here? Could I use romex or would it have to be conduit?