Yes, I had the same thought but decided it most likely isn’t the sister. The woman’s uniform looks to me like day-to-day duty fatigues and since two or three of the men in the picture were wearing almost the same uniform, I reasoned they may have been cadre of the new quarters/residences for the scientists and who were serving as “hosts” for Kim’s visit.
I wonder if those new residences will have electricity 24/7? I doubt it.
I think you are right and his sister looks like him, but less jolly