Just wanted to add my experience as my 60 day window opened up today. Majority of these are for a party of 2, but I'll note where my entire party was included:
Day 60 (July 22nd): nothing available for FOP (although, right on schedule, the website was down for the first 10 minutes, but I doubt that had any impact); plenty of availability for Na'vi
60+1: Plenty of TSMM availability; SDD availability began around 5:00pm (as of right now, still available around 9:00pm though); plenty of availability for A_S_S (ha)
60+5: Availability for FOP began around 10am for party of two, but was able to secure FOP for all 8 in party by splitting up into groups of 5/2/1 at 11am. As of right now, still showing availability around 2pm for party of 2
60+7: Availability for FOP at all times, beginning at 9am (not surprisingly) - can still book 9am as of right now as well
Overall, just about exactly as I expected, including difficulties with the website