I don't fly the Airbus, but why would the technique be any different from any circling approach: Runway in sight, disconnect autopilot, fly VISUALLY to the runway using PAPI/VASI for GS guidance. You will NOT have time to mess with radio tuning. You most likely will not have time to mess with MCP modes.
I didn't know that FOQA generates any warnings. GPWS Mode 5 should not activate unless the parallel runway is closer than the initial runway, and you "dive for the deck" to get to its GS. You should brief the possibility of a GPWS warning, as well as crosscheck criteria (e.g., PAPI display) that allow you to ignore it.
If you go all the way to sidestep minimums, you may have a hard time stabilizing on centerline by 500' AFE, so you may have to make an aggressive initial lineup maneuver, or go around and get a straight-in approach to the other runway.