Why?
Depends on the goal, IMO. When 'bulking', yes. When I cut, I drop carbs earlier in the day.
Why do you think the energy would be wasted? Excess calories are 'wasted' (more accurately, stored as body fat), but proper caloric intake and the demand for recovery due to training will not result in 'wasted' energy.
Agreed, in part. However your goal will dictate your diet, and cardio schedule as far as i'm concerned. If you're doing am cardio, I assume you're primary goal is to reduce bodyfat. That being the case, i'd stick with no carbs before bed, but would have a substantial meal, e.g. beef - a good combo of protein and fat. Even cottage cheese with a tbsp of natty PB, add some fish oil caps (not into the food lol) and you're gtg.