Thank you for the sincere comments! Your assumptions are mostly correct and perhaps it would be better if we had given another clue towards the Patient Zero (Spoiler: He is the only one spreading the disease and doesn't develop the symptoms). That is a difficult thing to balance cause if it becomes instantly obvious who is the patient zero, then the game loses replay value.
Regarding the theme of the gamejam, most of the characters are equal to each other and the goal is to find the only one who is different, but not in an obvious way, thus becoming a puzzle.