Gold makes more sense for Civ5. If energy exists, it wouldn't fill BE's role (which is the role of gold). IIRC, Civ4 had some concept of energy related to power plants. It struck me as overly complicated, but would be more likely to be used than BE's gold replacement.
Health could be used in Civ6 similar to Civ5 (although my personal preference would be a whole new mechanic instead). I actually think the penalties for health fit more with happiness and the penalties for happiness fit more with health (with the exception of rebellions). Civ4, of course, had both concepts, but did it in a way that was unfortunately a bit redundant (health, happiness, and city maintenance is probably not the ideal system). If they used health instead of happiness, luxury resources would have to have an entirely different purpose, though.