First, re: Ears - I've seen plenty of engaged couples wearing the ears, but some people like to wait until they're married to wear them. I think it's just personal preference.
Re: cancellation of rented DVC points - this would really depend on the person you are renting from because the penalty s/he incurs depends on his/her Use Year. If you cancelled more than 4 months before the end of their Use Year, they would not incur any penalties and could easily use or bank the points. If you cancelled within those last four months, they would be very limited in what they could do with the points (use or rent, basically), and if they didn't use them, they would lose them. So they would probably not give you your deposit back or, I dunno, they might ask for all the money! Many renters have contracts for you to sign that spell out what would happen in case of cancellation, so the thing to do would be to rent from someone who understood your situation and could work with it.
This might mean that all the Disney Vacation Club resorts are booked too, and it could be hard for you to get even a rental. Then again, Saratoga Springs seems to always have availability...
A good place to start looking is the DIS Rent/Trade board:
http://www.disboards.com/forumdisplay.php?f=29
It will give you an idea of how much points are renting for at the resort you want. If you are less than 7 months out from the date you need points, you can rent from owners at any of the DVC resorts. If you are between 11 and 7 months out, you will want to look for people who own points at the specific resort you want, b/c they are the only ones who can make reservations there before 7 months.
If you are looking for the names of the resorts and the types of accommodation available, check out this site:
http://dvc.disney.go.com/dvc/guest/resorts/resortOverview?id=ProspectsResortsOverviewPage
Once you know which resort you want and what size room, you need to find out how many points are required for that type of room at the time of year you are going. This page lists the
points charts for all the DVC resorts:
http://www.wdwinfo.com/disney-vacation-club/DVCpoints.shtml
The Rent/Trade Board will show you where and how many points are being offered at the moment. You can also put in a request when you know what you want, but you will need to follow the posting rules in the sticky at the top of the forum.
Yes. Each type of accommodation has a maximum occupancy number, and it can vary by resort. The official DVC website I linked to above will tell you the max occupancy for each room type at each resort. In general, it's 4 for a studio, 4 or 5 for a 1-bedroom, 8 or 9 for a 2-bedroom, and 12 for a Grand Villa.