While similar in appearance, neither of the cases you describe are typical of CCD.
What likely happened here was war (beekeepers call it "robbing"). The hive you describe from March was the defender in an all out war with another hive, the other hive likely took heavy losses as well. The pile of dead contained bodies from both. That was the battlefield. The attacking hive may have also died completely during the war, which is why there was still honey in the victim hive.
The winter loss you describe is indicative of the attacking hive in a similar war. An attacker that didn't win. Or perhaps did, but didn't gain enough honey for the queen to survive the winter. For some reason they lost all their honey stores (This can happen if yet another hive robbed them, or if the queen kept laying too many workers for the stores to support for too long after the nectar flow stopped). After the hive eats all its stored honey, it turns on neighboring hives.
CCD looks similar to these losses, but both honey remains (until it's scavenged by others) AND there are no dead bees to be seen. Such that it looks as if a perfectly functional hive just up and left.
My two hives went to war last summer, and the carnage was unbelievable. Hundreds of thousands dead in a pile in front of the "victim" hive. I didn't know why they went to war at the time, but now I know that 70,000 bees can consume a massive store of honey pretty quickly if they have no work to do. And I've also learned that if 3 days don't go by without rain, flowers don't produce enough nectar for bees to have any work to do. (It was VERY rainy here last summer)