[jivemi]

Thanks everyone for your prompt, informative and helpful responses. It was especially gratifying to receive confirmation concerning limited casualty reports with fast arty ON. That helps to explain why some dug-in infantry were eliminated after only a couple of direct-fire casualties. (BTW this was an AI-generated campaign battle so there were no "customized" preferences or unit capabilities--I always play with stock values at 100%.)

Nobody took a stab at question #3 though. No doubt it's an arcane issue which is both complicated in theory and risky in practice. The bottom line is, heavies definitely cause casualties and given enough saturation can drive infantry from their holes. A most useful thing to know. Thanks again everybody!