I don't think Hasbro would let anyone die (I'm not sure Sombra really counts as he was a smoke-thing and didn't really seem like a pony at the time) in a show about friendship. The worst that might happen is Celestia isn't just captured, but gets permanently stripped of her powers.
If the movie really is the ending (which I still don't believe), then I expect for Celestia and Luna to return to whatever realm they came from, leaving Equestria to Twilight (and Cadance I guess).
Anyway, stuff from Bronycon interviews!
GM Berrow
* McCarthy was the one who provided her with the detail that Cadance used to be a pegasus for the first FiM chapter book. Berrow says that means it's canon.
* She was the one who chose the names Marble and Limestone for Pinkie's non-Maude sisters, because the initials of those three spell out "MLP".
Bunch of others
* Possible costars that de Lancie is interested in bringing onto MLP are opera singers he's worked with, Bryan Cranston, and William Shatner; I guess they're on good terms after all.
* In response to the accusation that Discord has become less chaotic now that he's good, de Lancie claims that Discord shouldn't be too nice and there may come a time where he acts "naughty" again.
* Charlotte Fullerton says that in the crazy cat lady scene of "Suited For Success", Pinkie's original last line was, "It's a slippery slope," instead of, "Give her time." I prefer what they went with.
* Rarity's fainting couch is unlikely to return; she has apparently grown out of it.
* The writers don't know what's causing the current hiatus, but suspect it's due to Friendship Games using the same cast and crew.
* Berrow said that a little girl once mailed her asking for her to be her Celestia and exchange weekly letters. Aww.
* "Amending Fences" was almost canceled late in the process, because guys at Hasbro noticed that Twilight had previously appeared in scenes with her Canterlot friends while they were just background characters. It's still surprising to hear about guys at Hasbro caring about continuity like that.
* In response to a question about how Rainbow Dash and Rarity didn't seem like they were achieving their professional aspirations, Fullerton reminded everyone that just because they haven't yet doesn't mean they won't, and Rogers said in particular to be patient about Rarity.
* In what's probably already known but is news for me, Larson wrote an early story for Gravity Falls. At the time, the characters weren't clearly defined and there were few script references, so he didn't enjoy working on the show.
* Episode premises that never came to be (directly quoting for this, names edited for consistency with the rest of my post):
Rogers: constant pitches for seaponies from her and just about every other writer every season
Berrow: Applejack secretly becomes a guerrilla artist named "Flanksy"
Larson: "Fillydelphia Ragtime", in which Applejack and Rarity went to Fillydelphia for a friendship problem and discovered that newly-elected mayor Flam had banned cider inside the city, resulting in AJ starting up a bootleg cider operation to keep from losing the Fillydelphia cider profits her family depended on
* After Unicon, the show writers were told by Hasbro that they couldn't attend any more cons, but they continued coming anyway. Writing this out, I feel like I already knew this, but whatever.
* It looks like Larson's
Pennyroyal Academy series is working out well for him.
* Also probably already known but news to me, Larson worked on Sym-Bionic Titan.
