If you are only at the bidding stage of resales right now then a closing in August is being very optimistic on your part IMO. From agreement on a contract to being able to book a room, my resale took 11 weeks and 4 days (just 3 days shy of 3 months). That said, other individuals have been more lucky than me and it is not impossible to close within 8 weeks of verbal agreement. If you have definite plans to go in October (i.e. plane tickets and time off) then I would do as bobbiwoz suggested and book something else, just in case. If you only book a hotel room through Disney (and not a "package") you only have to put down one night's deposit and can cancel within 5 days of arrival. If you do close in time to be able to book something else, then go ahead and cancel and book with your new points. It is not impossible to find availability even a few weeks out if you are willing to take what you can get and usually do a split stay but it does really depend on the time of year. As noted, October is VERY busy with F&W stays so you may be completely out of luck by then.
Terri