Yeah, taping of the Christmas Parade and special guests have usually happened the first full weekend of November, and sometimes additional taping is done the following weekend. When the taping of the parade is done, they usually don't have the Christmas Tree up, as they often place a camera and/or stage area there. After the parade is taped, then they can place the tree in it's spot. So they will often do additional filming a few days after the parade filming, and sometimes they don't finish the taping until the following weekend. Last year they did most of the taping within just a few days, whereas previous years they did the taping primarily on the 1st two Saturdays in Novemeber. It looks like last year, they were working around Ryan Seacrest's schedule, so that's probably why they broke from their normal filming schedule.
They also have at least two special guest singers that they tape. One of the stage areas is always in front of the Castle, so keep your eyes open for when they start constructing a stage area in front of the castle. That's the sign that special guest taping will begin any day. Usually the taping is done first thing in the morning.
As far as who the special quest singer(s) are, Disney doesn't announce it ahead of time. But, sometimes word leaks out the day before. The day they do the taping, Disney does place signs near the entrance of DL and near the area where the taping will be happening, to inform guests that by entering the area, guests are giving permisision to have their image appear on tv, along with all the legal notices they are required to disclose.
As for the 2nd special guest signer, that location can vary, from year to year. Last Year they did some taping of Anika Noni Rose in New Orleans Square, where she sang a song from Princess and the Frog. This year, it would be expected for them to use as least one song from Tangled, so I would think they would do some taping of the meet and greet area that is being worked on in Fantasyland.