Best TRIAC for zero cross detection
You have an MCU of some type that you are using to control those inputs to the opto-isolators. I suggest that you get rid of the one problem with the switches by instead wiring in low voltage switches directly into the microcontroller and let the software resident in the microcontroller provide for the override function.

Rate control (dV/dT) problems with triacs can still exist for cases when the AC power is interrupted or applied.