So do you think the "Hillary is behind Troll Trace" plotline was created after she lost? Because it is fact that the episode they'd originally made, their entire plot for the season, revolved around her winning. This is a thing we know and they joked about.
Because, if not, then literally the only part I'm making any assumptions on is Garrison coming back to counter balance Hillary.
No, it is not fact. Nobody knows what they planned to do. I would even say that the season was leading up into Member Berries being behind everything, including troll trace, and manipulating everyone. There were hints of something more sinister coming, "the REAL Stormtroopers", before it was dropped. Likely the resurrection of Hitler and a Nazi Zombie army. The scene with Hillary behind Troll Trace was shoehorned in at the last minute and felt detached.
Shit, they even ended the ACTUAL season with Troll Trace being defeated and the internet being reset by reactivating the Skankhunt troll network and overloading the system!
That was definitely part of the rewrite, a last minute effort to wrap up some of the loose threads and put the entire mess behind them. It was a reset button on a botched season.