Fox previously owned the rights to all characters connected to "Daredevil", including Wilson Fisk. Of course now since the rights reverted back to Marvel Studios, they would be able to use the Kingpin. Sony does not own the rights to Kingpin as he's considered a "Daredevil" character despite first appearing in "Amazing Spider-Man". If they wanted to use Fisk, I assume that some kind of deal would have to be reached. I don't believe he's an interchangeable character like the Maximoff twins are.
That is interesting regarding Hart. Been behind...have seen the recent trailers and footage what not. I can't wait to see the pilot.