Shout out to Clawdya for the information.
I called a 3rd time this afternoon to ask about my Dec 30th reservation. Explained what the two other cast members had said and also said somebody i knew had an 11 pm reservation. This cast member seemed completely clueless and started to read the description of what the dessert package was....it includes this, you check in 1 hour before, blah blah blah. Then she read, there are 2 fireworks that evening one at 7:30 and one at 11:00 (I suspect it's supposed to be midnight). And I said, yes...I wanted the 11 pm one...the later one. I emphasized this in both my earlier calls. She putters around her computer and says she's asked a colleague because she didn't know there was an 11 pm booking time. They have to put the time in for it to show up... All this time I'm waiting for her to put it in ... but she continues to play around on her computer doing who knows what. She says...after 15 minutes, I'll put that time in and see what comes up. Nothing .... she says it looks to be full. I said, "if nobody know knows there's an 11 pm booking time then how can it be full?" She putters around the computer again and she says, "I'll check the venue itself ...." and then she hung up on me. And the voice that talks about the survey came onto the line.

arrrrrrgh
So I call back, got somebody else ... explained that I had just spent 20 minutes and I didn't really want to say it all over again. At this point, I was frustrated and mad and having a mini-melt down because the last CM seemed to be so infuriatingly slow and plodding.

Anyway, this one was calm, didn't know about the second fireworks either...wondered if you had to check in at 6:40 and come back for the 11 pm fireworks. uh... no. I said I've done this before. You don't eat your dessert, leave and come back 4 hours later. She tried the time of 11 pm, got nothing. She then tried the venue itself. Found me an 11:05 pm time slot ... don't know how. And NOW, I am sure we have the Fantasy in the Sky fireworks.
So here's the hint when they try to put you in at 6:40 or 6:30. Insist they search by venue. Putting in 11 pm won't work either....they only seemed to find it when they searched on the Tomorrowland Terrace.