The Pinkertons TV show has a factual error in that Will Pinkerton claims that his brother Robert (working at the Chicago office) is his twin brother. This is not true, historically. William is older by two years. Robert did have a twin sister Joan when he was born, but Joan died when she was only seven years old. That same year, though, another Pinkerton daughter was born, and she was named Joan too. It's a sad fact of history back then that many children born did not survive to adulthood, and names were sometimes reused like this. (Not to mention that Allan named his sons William and Robert after his own brothers.)
Anyway, in the "Case of the Dead Dog" episode, Kate Warne claimed to have met Robert Pinkerton already, and it didn't go well. He was fervently opposed to female detectives, and perhaps that's why Allan avoided introducing Will to Kate for years. I suppose this saves on having to hire another actor, if the brother Robert ever decides to visit Kansas City. Kate is cagey about her own family. She admits to having a brother named Virgil in New York state, but neither confirms nor denies having any other siblings. I am not sure what to take as historical fact given the clear error about Will and Robert Pinkerton. The episode's mystery revolved around brothers too, and whether such bonds can survive betrayal.
It's interesting that the Empire show is about fraternal rivalries and manipulations too, even though Hakeem and Jamal like each other. And though King Lear was mentioned in the pilot, the show is about brothers rather than sisters vying for control. The creators also make analogies to The Godfather, with the criminal family and the son who is reluctant to take over the dynasty. I suppose that conflicted jealousy leads to brothers both loving each other and hating each other, trying to compete with each other and trying to protect each other, with varying results. Maybe this is what attracts me to Arrested Development as well. But there the illegal schemes and Boyfights were portrayed comically instead of with soapy, murderous drama (at least until season 4). I guess it's fitting that Imagine Television made both shows. I do wish that Netflix would make some definite announcement about a season 5. The TCA winter press tour has been going on so long, and no interesting news is forthcoming; it's just network spin and publicity.