Well, you could if your freezer is big enough, but pumpkin tends to be mushy when thawed.
No, the process of freezing will make the pumpkin turn to mush very quickly.
Yes, I've frozen mine for quite a few months. However, it will be watery when thawed so it must be strained.
I have a neighbor who did it, it turned out ok, wasn't the best tasting though. Pumpkin freezes best if cooked. Either cook the chunks first, or cook and puree, before freezing, depending on how you plan to use it.