It’s hard to say, especially with the second class still up in the air on where they’d fall in a conflict.
Given the tension between Bess and Jinju, I’d wager the second class would skew mostly in favor of maintaining class hierarchy, which would pair them with the first.
Who Will Control The Train If There’s A Revolution?
A potential team-up between the tail and third class would make for a solid revolution aboard the Snowpiercer, but is that a better bet for victory than the first class with the power of Commander Grey and the Jackboots?