Aang got his tattoos after inventing the air scooter, right? Therefore Meelo inventing and mastering his own sub skill of air-bending (i.e. fart-bending) has technically qualified him to be able to receive his arrow tattoos.
So we know as soon as we enter America from dialogue picked up around us that slavery is still a thriving business in the Nazi ruled America. We hear a woman claim that she just recently put two “hard-working slaves” up for auction, and we know that BJ’s dad is more than willing to step on the heads of those he, deems lesser than him to get ahead in life. When BJ finally reunite with his father, he claims that he has a 2000 acre ranch, but we know from flashbacks that he himself is a lousy rancher. I do not think it is a stretch to assume that BJ’s dad has a thriving slave plantation that we never get to see.