Both actor 'Ray Stevenson' and director 'Jonathan Hensleigh' have been with The Punisher film series (despite all three films have been reboots). Ray played The Punisher in Punisher: War Zone (2008) and Jonathan directed The Punisher (2004).
Danny Greene became such a folk hero in Cleveland that a young admirer penned a ballad in his honor. It reads in part, "...They shot him down and blew him up With most regular persistence. Through guile and luck and skill, Danny Greene is with us still. Some day he'll die, as all we must, Some will laugh but most will cry. His legend will live on for years, To bring his friends mixed pleasure, For he has done both bad and good, And lived his life full measure."
Julius was actually killed from the backseat by Ray Ferritto in 1969 in an LA airport parking garage, several years before its portrayal in the movie. Ferritto used the sound of a jet passing overhead to mask the sound of the gun going off.
When at the fruit market, Danny is holding a shopping basket. The basket is a present day basket, made of plastic. Baskets during the early 1970s would have been made of metal.