I'm following along just to see what FD is like this year. I'm hoping that we can get it in 2018.
I did book FD in 2015 for 10 of us at POP. We needed 4 rooms. I was so nervous that I wouldn't be able to get them all. We had word the night before it was supposed to drop so I had 2 laptops/devices ready to go. I woke up around 1:00 PST and found that FD had gone live. I booked two rooms under my
MDE on one device. I don't remember all of the steps but I do remember that it was not an extra step to put a different name on the second room. It would have been more steps to book the room under a different MDE though, so I stayed logged in and just entered the other name (my brother and family). I was logged into my parents' MDE on the other device and booked their room and then my sister's and her family on their MDE. I made sure that all of our MDE's were linked and ready to go. I also made sure that I had my credit card added to both accounts. I just used my card for all of the rooms and got reimbursed. That helped to save some steps too.
It worked and I was able to get all 4 rooms. I think it helped that we were booking at POP as I think they had more availability than some of the moderate resorts. I hope my experience helps! Good luck!
ETA: If your accounts are linked previously, I think all you have to do is click on the names and not enter each of them in. At least it was the case when I booked.