Persistence! Keep checking online multiple times a day because cancellations will come up when people change their plans. With the credit card guarantee people will cancel so they aren't charged the $10 per person penalty. You can also subscribe to the February cancellation thread:
http://www.disboards.com/showthread.php?t=3178762
As far as booking for 3 or 4. It is harder to find a reservation for an odd numbered party because of a quirk in the Disney system. The system wants to fill every seat at a table so even though a party of 3 will often be seated at a 4 top it won't let you book the table. So add 1 to your search and look for a table for 4 and you might have better luck. When you arrive at the restaurant just let the CMs at the podium know there are just 3 of you. As a party of 3 we have had to do this frequently. Also, as long as at least one person shows up for the reservation, you will not be charged the no show fee for the "missing" person. Everyone who will be at the table must be included because of fire code regulations so
don't reduce your party to 2 and try to add a third person at the podium.
Whether you can walk up and be seated or not depends on how busy the restaurant is. Some have been successful, others have not. The second week of February includes Valentine's Day. I doubt it would be easy to get a table as a walk up on that evening, but maybe another week night. Most recommend trying to walk up when it first opens for dinner or near the end of the dinner seating.
If you cannot get a reservation, lunch is a CS so no reservations. Some people have been in the FP+ test and have been able to reserve lunch times, but this isn't available to everyone at this time. You can line up on the bridge and generally the line moves pretty fast. The menu is different (except for desserts), but you can see all 3 rooms and the decor. The biggest differences are at dinner you have a photo op with the Beast after you dine and alcohol is available.[/QUOTE
The specify they will charge $10 per person, are you sure they won't charge for the missing person?