>>141699
You fast every day unless you're eating constantly. When you wake up from sleep you are in a fasted state. This is where the word breakfast comes from - breaking fast. Train before you eat anything is what I'm saying.
>>141709
Cardio will basically increase your metabolism in general. Recovering from cardio will mean less gains in the immediate short term sense, but being in better shape from cardio means you will have more efficient cellular metabolism and cardiovascular health, which is good for building muscle and not dying in a sauna of a heart attack.
>>141710
You shouldn't wait 72 hours between training sessions most of the time, so no. It's easiest to do cardio on your rest days to put distance between cardio and lifting.
>>141735
This is all true, but I will add that cardio should always be done fasted to burn as much fat as possible, as the boost from carbs is irrelevant to doing cardio. Only bother with the carbs if you're going to run a race or something as opposed to regular cardio for cardiovascular health.