It's revealed that DAA came into being in 1984, when Miles became partners with Jack Ashley and Duncan Arthur. Earlier the company had been known as Ashley & Arthur, founded in 1947. It went public in 1979. Miles is the largest stockholder with 30%.
When Michael is arguing against administering polygraph tests, he tells Miles that he can't start with Mark (a black man), then next he mentions "or Wasserman, or any of the women for that matter," implying that Angel Wasserman, in addition to being female, is Jewish. Michael says the only way to avoid the appearance of bias is to start with himself. Yet Michael is Jewish, also. It can be argued that he's also the most powerful man in the company besides Miles, which eclipses his minority status, but it still seems to undermine his argument about bias in the selection.
The use of a spy in the guise of a plumber is a sly allusion to the White House "plumbers" group that operated during the Nixon administration. This group of White House operatives, which included E. Howard Hunt and G. Gordon Liddy, engaged in many clandestine and covert activities, sometimes illegally, on behalf of the president.
Polly Draper, Peter Horton and Melane Mayron are credited but don't appear.