Yes you can do it on the weekend. We did ours on a Saturday. Actually, our photographers said that it is usually less busy on those mornings and so it is easier to shoot. There were still lots of workers when we were there though.
The Disney photographer picked us up at our resort shortly before 6 AM. We were staying at the BWV that morning, and by the time we made it from our resort to the front of Cinderella Castle for our first photo, perhaps 15- to 20-minutes had elapsed.
Here are the timestamps for the first & last photos that were taken that morning:
First Photo: 6:13:34 AM Last Photo: 6:51:01 AM
After that last photo was taken, we got back into the Disney van and our photographer drove us back to our resort. It was a very quick in & out kinda morning.
The Disney photographers have the photo session down to a science. They probably last anywhere from 60-minutes to 90-minutes for most folks.
I was cleaning up some files in one of my external hard-drives. I stumbled into the "DEP Wedding Photography / Videography Service Order." I thought I would reprint below what was stated in my document:
Description:6:00 a.m. pickup at your Walt Disney World® Resort hotel; Portrait session at various Magic Kingdom locations; One 12-print 4x5 white Disney-themed folio; wedding attire for bride & groom
Start Time:6:00 AM End Time:7:30 AM - - - - - - -
Please note that the timing may vary from FTW couple to FTW couple, so pay close attention to what is stated in your photography service order.
All prices are not locked in till 6 months out so if they quote $800 at 7 months then it may not be the rpice you pay as they will only honor the price at 6 months is what our planner told us