The points expire midnight of your checkout day. By points I mean the dining/QS/snack credits. You get each equal to the number of nights you stay. 4 nights, 4 of each (assuming the regular dining plan).
If you are saying that you want to stay beyond the end of the promotion then you are fine. FD is based on your check in day... You could check in on the last day of the promotion and still have FD as part o fyour package for the entire stay.
Last week I booked our 2011 free dining vacation online. The end of the promotion is 9/29/2011. We are checking in 9/29 (which is our anniversary ) and staying until 10/8. Had no problems.
Yes, but you have to be booked originally with the free dining package, and there has to be room at the resort of your choice for the free dining code.