"Mr. Pain" is played by William Morgan Sheppard. Young "Mr Pain" in the film and photo is Mark Sheppard, his son.
This is the first time that Mark Sheppard and William Morgan Sheppard have played the same character. The second time was on Doctor Who (2005).
The reason there is no J street actually has nothing to do with the time period, it's just how cursive is written. But the rest of Jimmy's explanation was correct. The capital I and J look quite similar, so they had to pick one, and the I won't be confused with another letter, while a capital T is almost exactly the same as a J.