Probably the last installment since the field of exercise science is not expansive and I am no expert.
Cardio of some sort has a benefit for everyone, even if mostly doing strength training. It has been proven to help recovery http://suppversity.blogspot.com/2012/10/cardio-weights-mutual-exclusives-or.html and it creates satellite cells that are the precursor to muscle fibers http://suppversity.blogspot.com/2011/11/hit-your-sattelite-cells-to-increase.html. There is also a study that show VO2 max being correlated with better nutrient partitioning (whether your body spends nutrients on muscle or fat) http://suppversity.blogspot.com/2013/06/bulking-done-right-what-can-latest-100.html.
So the question is not whether you should do cardio, but how much and what kind? HIT seems superior in pretty much every way: less effect on strength training, better VO2 max increase, more satellite cells, less time. Also it is way more fun (and useful) to sprint. Which doesn’t mean that long jogs aren’t good as well, but I don’t like cardio that much so I want to do as little as possible. Try not to do it on a training day or do it after and at the opposite end of the day for best results.
One of the more persistent myths is that you can eat all day and keep your metabolism humming along to burn more calories. This has been thoroughly debunked now for twenty years, yet I talk to intelligent people that still think it is true.
That said, it’s not completely without merit. Studies have looked at how you consume your food during the day; spread out or all at once and at various amounts of protein. The results seem all over the map with some concluding that a large bolus is better, while others show meals every 3 hours are better. It also seems to depend on your age as if your body’s response to amino acids weakens as you age. What is clear is that when you reach a threshold of protein ingested in one meal it turns on muscle protein synthesis and that it takes about three hours for the amino acid concentration to fall again. At this point another another bolus of protein could turn MPS on again. Theoretically a feeding strategy might lead to more muscle growth, but empirically significant results are not available yet. However, a study on athletes showed that those who snacked gained more lean mass and lost more fat.
More importantly, is your pre-bed meal. Sleep is vitally important, probably more important than anything but training. You can make it even better by ingesting some casein protein before bed http://suppversity.blogspot.com/2012/02/32kg-of-lean-mass-over-nigth-w-40g-of.html. This is a much more significant result than any of the meal frequency studies have shown. It might even get me to purchase some casein powder if we are talking about 7 pounds of muscle in a year.