Short answers (it's after my bedtime) - I can provide further details if needed:
Reverser - on the 737-300/400/500, the thrust control is hydromechanical. If the T/R deploys uncommanded there is a mechanical linkage that will retard the throttle to idle. On the NG, the thrust control is FADEC (EEC) - if the T/R deploys uncommanded, the EEC will electronically retard the thrust to idle, but the thrust levers won't move.
Hard Alternate:
Hard alternate is an unrated mode, roughly equivalent to the old hydromechanical fuel control. Hard Alternate will always provide thrust equal or greater than the same thrust lever position in Normal mode. At corner point temperature, thrust will be basically equal between Normal and Alternate mode. Below corner point, Alternate mode will be greater - quite a bit greater if the temperature is much lower than corner point.