Two independent questions and two independent answers.
1. If loco is HOG enable and HOG mode in ON, then no need to start generator.
For example Jaipur-Jodhpur high court express run on HOG ON mode on full diesel route.
2. Generator is not ONLY part of an EOG coach, it also contains Luggage room and guard cabin. So only HOG ON mode is not...
more... sufficient to remove EOG coach.