Just think about it for a sec, Twilight is teaching Starlight about magic and friendship, and she made friends with both Sunburst and Trixie earlier this season, and Big Jim said that Trixie's story isn't over yet! It leads me to believe Trixie might be coming back in the finale!
But it's not just Starlight that's been making alot of friends - it's Spike too! He made friends with a Dragon Lord's daughter, and he's going to make friends with a changeling and Discord! John de Lancie also said himself that he voiced Discord in TWO episodes this season, but there's no other Discord episode in sight other than Dungeons & Discords, and John himself said that he thinks his second role might be in a 2-parter, which could be none other than the finale!
Another thing to add: Spike was HUGELY supportive to Starlight during the season premiere! He was more supportive in this premiere than any other season (other than 3)! He didn't interact with her that much since then, maybe perhaps because Starlight needs some moments with just Twilight, as well as the Mane Six.
So basically what I'm saying is, I know Starlight will be playing a major role in the finale because it's obvious, but perhaps Spike is too, as well as the friends they made this season like Sunburst, Trixie, Ember, the changeling, and Discord! I don't know what the finale is gonna be about exactly, but I do think it has something to do with this being the solution!
What do y'all think?