My fastpass window opened today, I had no problem getting anything for any time of day, but I was booking both SDD and FOP at day 6 and beyond of my trip.
I went in just now and poked around and on Day 1 of my trip, there are no longer any SDD fastpasses available (I didn't attempt to book one for that this morning, so I can't say if there was availability at all at some point earlier, I went for TSMM for day 1), but lots for AS2. When I look at my DHS on day 6 of my trip, there are plenty of SDD availability from early afternoon right through the evening and AS2 tons all day. My AK day is not until Day 7 which is still showing FOP available throughout the day.