I don't know exactly when the preview is shown, but here it is:
https://www.youtube.com/watch?v=fVvNLfJ5eJw
And here's a translation I did with the help of a friend:
King: ...It's finally come...
Now that Advent has fallen, we can already declare the downfall of the reformers.
Humanity greets a new era...yes...by the waves caused by the messengers of the Taiji...
Queen: Humanity greets a new era...
But there's still much to do before then.
So open your eyes, Asakim Dowin...
Asakim: (ellipsis!)
PREVIEW
When the prison is destroyed
Another Earth appears
SUPER ROBOT WARS Z SERIES
FINAL CHAPTER
Hibiki: Kh!
Suzune: At this rate we'll...
Hibiki: Dammit! DAMMIT!!
The blue planet and the green planet...
What is the fate of these two Earths?
Misato: Shinji!
Shinji: I don't care what happens to me! I don't care what happens to the world!
But...at least Ayanami...I swear I'll save her!
Kira: How could...what's the reason...
Shinn: Pull yourself together, Kira!
Athrun: At this rate, PLANT will...! They're putting us on a direct course for devastation!
Mineva: ...That boy's burden is heavy.
Barnarge: Audrey!
Mineva: (Farewell, Char...Barnarge...)
Char: That's the truth the Laplace Box is hiding...
Frontal: You could certainly call it proof of God's existence, couldn't you?
Char: And protecting that is Chrono's doctrine...
Graham: Cutting a path to the future...isn't that your battle, Setsuna F. Seiei?
Feldt: Setsuna...
Setsuna: (ellipsis!)
Graham: Have faith that he'll wake up.
Alto: Ranka, I...
Ranka: Don't say it!
Alto: (ellipsis!)
Ranka: Isn't it strange...I was able to sing in the middle of battles, but I was always...always too scared to ask Alto how he really felt...
???: Isn't that heroic?
Ranka: !
Amata: Kagura...!
Kagura: Yeah, let's do it! With the power of we three, we can regain the Sun!
Amata: Uooooooooou! A-Q-U-A-R-I-O-N!
Kaname: ...Sosuke...
Sosuke: Chidori!
Kaname: ...Farewell...
Sosuke: CHIDORIII!
Kaname: (ellipsis!)
Chirico: ...!
???: That's right, Chirico. That is your undeniable fate.
Chirico: (ellipsis!)
Lelouch: !
C.C.: That's right, Lelouch. That is the duty that's been imposed upon you.
Lelouch: ...Very well. If that man could do it, there's no way I can fail!
Go: Draw forth the true power of your machines.
Kouji: Mazinger's true power...
Ryoma: Shut up, Go! You can't just make Getter Rays do whatever you want!
Kei: Repair the true dimension...?!
Olson: That's right. That is your...our duty!
Noriko: Even if over 12000 years pass on Earth, I won't have any regrets!
That's Gunbuster's...that's a Buster Machine pilot's duty!
Hibiki: Miss Suzune?!
Suzune: Now you see, Hibiki. This is the truth behind the Genion.
The ultimate enemy of many worlds...what is its true form?
???: Well, what shall we do?
???: It's been decided. The Earthlings from that planet shall be erased.
That is our duty.
Beyond the Prison of Time waits the Prison of Heaven...
Now, the door opens.
SUPER ROBOT WARS Z 3: TENGOKU-HEN
What will humanity see at the end of the legend?
Takeaways:
-Third Impact from Rebuild
-I don't know Aquarion personally, but I have a friend who's very fond of it and says that based off of the preview, they may be taking the plot in an entirely original direction.
-FMP scene is from "Continuing On My Own", specifically the part where Kaname goes with Leonard Testarossa in order to keep Amalgam from threatening her school or Sosuke anymore.
-Consensus is that Noriko's comment pretty well confirms Diebuster
And if anyone really doubted, Z3-2's official name is "Tengoku-hen", which is normally the Japanese word for "Heaven" (written with the kanji for "sky" and "paradise"); here though, the "koku" used means "jail" or "prison". So the English translation could be rendered as "Sky Prison" or "Heaven Prison".