Short story that happens at the EXACT same time as "Return to the Mirrorverse". While the Mane Six and Spike are busy helping Captain Goodguy and Chrysalis against the super-charged Erroneus Equines, the Mirrorverse versions of Trixie, the Flim Flams and Derpy are busy helping their recently reformed versions of Celestia and Luna re-learn on how to deal with situations in a completely just manner and save violence as an absolute last resort.
I can't say I really liked this much. First off, the whole plot element of throwing in an OC who likes Trixie distracts from the rest of the fic entirely, to the point I found myself skimming. That entire element could have been cut out and the story would be shorter but much tighter and easier to read, IMO.
Second, you don't need to add 'Other' in front of a pony's name nearly every time. We get it, this is the Mirror Dimension.
There doesn't seem to really be much of a differentiation between Luna and Celestia in their reformation, despite one only being evil for a couple of years while serving Sombra in the rest of that time period, and the other being evil for a thousand years.
Finally, this thing is littered with spelling mistakes and poor word choices, and could use editing. A few examples.
Equestria Prime
Heartbreak
In the words of emperor kuzco....
I Hope The Special Guest Appearances are Markiplier, Scott Cawthon.... and Charlie Sheen!!!.... What? you put Charlie Sheen in FNAF 1: MLP Style. That was pretty funny when put him on there!