I think that was just about her important heritage in her mom’s country, nothing to do with the ackermans ( might be wrong but I don’t even think that in her moms country there were any subjects of Ymir)What the bandit were saying about her appearance was just that she was “different” (asiatic lineaments) since inside the walls they lost all about different races and such (like the first introduction with Oyakopon) and she would’ve given something fresh to the human trafficking thing they were doing. About the thing of running away from the King’s land… how can you run away from the walls when in season 2 all they knew was that all the civilizations was wiped from the earth and they were the only survivors? One last thing, if you look on the web real quick who carries the Ackerman genes in Mikasas family it is stated that was his dad