1. Yes - but both engines will go to TOGA thrust.
2. A/T will be in armed mode as TOGA is a thrust mode not a speed mode.
3. See reply 1 - both engines will go to TOGA thrust. You are in a Thrust mode not a speed mode and the aircraft will accelerate.
I don't agree with the last part of the previous post - cruise thrust is less than TOGA so TOGA will produce more thrust. Same for the thrust limits - CLB/MCT may have the same thrust limit at high altutude but TOGA limits will be higher.