Of course the SEC does not "treat prospective witnesses equally". Morgan Stanley's board of directors was represented by Mary Jo White (MJW). Pequot was represented by Fried, Frank, Harris, Shriver & Jacobson (FFHSJ). So? Who is MJW? Wasn't she the US Attorney for the Southern District of NY who in 1994 wanted to prosecute Joseph Jett on preposterous charges that he orchestrated single-handedly a fraud against GE subsidiary Kidder Peabody in which he mispriced $23 billion of securities by $330 million? Who is a FFHRJ partner? Former SEC head Harvey Pitt. Now we can't think SEC and Justice Department personnel can by influenced by big jobs when they leave. Perish the thought. They are public servants.
If you are sufficiently simple-minded, you might think the SEC and DOJ are extortion rackets. As for the statute of limitations: look at a case like US v. West, 22 F3d 586 (1994). I think the lawyers' actions could be prosecuted by an ambitious AUSA. However, such AUSA would never be offered a $3 million a year job working for a big Wall Street law firm. What's the charge? 18 USC 1510, obstructing the operations of a federal agency. Tune in for the next installment of "As the Federal Agencies Turn". This is a soap opera.