(c) Vmcg/a should only be a problem for a very lightweight takeoff at, or near, min speed schedule. One of the saving graces is that the light aircraft typically will be accelerating rapidly and, by the time the pilot increases thrust, the actual IAS will be somewhat higher than what the takeoff was predicated on.
We do an exercise in initial training and every 2 years in recurrent that illustrates the effects of Derates on VMCg. The scenario used is a contaminated runway. The difference in VMCg between Full TO and TO2 thrust is significant. The urge to add thrust after an engine failure would likely result in catastrophe, if followed.