DVC occupancy isn't a very good indicator of the park crowds. DVC is designed to be full every night of the year. (FWIW, many DVC members love to go during the times the parks are relatively uncrowded).
So true! DVC almost always booked out but crowd levels rarely reflect that.
Oct weekdays are still pretty tolerable especially at night.
Watch out for Mickey Not So Scary Halloween Party nights, they kick you out at 7pm.
Epcot's World Showcase will be busy on Friday and Saturday nights due to the Food & Wine festival. If you are planning to be in Epcot in the evening and especially if you plan to check out the food booths in the WS, go on a weeknight. Other than that, we don't find October to be too busy and the weather is usually very nice at the time you'll be there. It's a great time to go.
In theory, all DVC villas should be sold out year-round. The most obvious variation is how quickly they happen to fill during certain times of the year.