Hey,
Thought I'd include my voice in the conversation. Since this is basically an argument of "how we get to X number of people in the same party" I want to add my own theory in the mix:
TLDR: I think DiKs and HoTs will throw a campus wide party, and the Alphas are not invited.
Let me explain: In the last episode, we see Magnar throwing more gasoline in the fire by sending new letters to the Alphas. I find it personally hard to believe that the new conflict could be resolved in 1 episode. Secondly, Caleb makes the point that Chad is hiding something, which is true.
What do I think will happen? At some point in the episode, Caleb will expose Chads secret and he will be kicked out of the Alphas. This will send shockwaves around campus and as a result, Sage, who has kept Chads secret will be furious and sever all ties with the Alphas. (Or this is the point where Sage finds out and after a bit of soul searching will come to the same conclusion.)
Then as a show of solidarity the DiKs and HoTs will plan a massive party with everyone except the Alphas. This would explain why we see Chad, MC, Sarah, Mel and Arieth in the same room together (but no other Alphas).
And you can still get to the required number of participants, as long as you include some unnamed characters. I just think this would make more sense than everyone resolving their differences, since we still have 1 more season to go.
Happy to entertain other viewpoints, of course!