Wan and Yeogyeong probably continued to fight for independence, I think, and I imagine they married somewhere along the way. Yeogyeong always said no to Wan at first for everything, but ended up thinking things over and trying them eventually. That's why I think they married (and probably had children).
I don't know what would have become of the Jirasi gang. Did they stay together? Did they split up and move on, leaving their Worry Organization days behind them? Taekgu was a liability to himself because of his drinking and his "loose lips" when drunk.
The one I can't figure out is Suyheon. He could never use his cover as a pro-Japanese officer again. And he was heartbroken over the losses of Min and Songju. Maybe he resurfaced somewhere, though, and continued to fight for independence even harder because of his heartbreak. Maybe he worked from outside the country. I just don't know.
The very ending was so silly (and I’m saying this as someone who really liked the show) that it’s hard for me to take a serious look at what might have happened to the bunch. But, it seems that Wan was indeed a changed man, and he and Yeogyeong likely headed north, perhaps into Russia. They probably met up with somebody like Professor Choi (of “Seoul 1945”) and underwent mandatory Marxist-Leninist indoctrination.
Suhyeon didn’t seem like the type to turn tail and run, and with his identity now exposed, he probably went underground to wreak a little havoc. Which probably explains all those dead Japanese officials popping up here and there.
With the “Monthly Jirasi” shut down, the gunsmith/machinist guy probably also went underground. I sure hope he comes up with a simpler design than the ridiculously complicated 1896 Mauser pistol they showed him making midway through the drama show. Building one or two guns a year just isn’t going to be enough to get Korea liberated from the Japanese.
I never figured that the other Jirasi guys really had their hearts into the revolutionary struggle, so they probably just headed for the hills and laid low until the Japanese defeat - whereupon they could emerge from the boonies and trumpet their past heroism to anyone who’d listen.
And, with the departure of Wan, Sachiko must have gone looking for someone to write Volume II of the story about how she was hatched from an egg. ;D