A. I've seen some say that for extended aerobic conditioning activities like distance running, the morning workout without breaking fast is a good one because it helps train the body to burn fat for energy. I don't have any references to good hard evidence for that hypothesis. Other than that, I don't think time of day is all that important. Making the time consistently is far more important.
B. I don't think I would want to do a hard leg strength workout before going out to run.
C. I'd try to go for the full hour. I'd rather have those 20 minutes be in the low aerobic range.
D. I'd take the short breaks over long breaks, at least I think as far as aerobic endurance goes keeping the breaks short will prevent the body from cycling down from the aerobic stresses and then going back up again. I think you'd get a much better overall aerobic conditioning by keeping the breaks short if possible.
