I don't think the BRF would meddle in a US criminal investigation. There have been plenty of royal sex scandals over the years, including Koo Stark, Fergie and her toe-sucking BF, Charles and Diana and their affairs, Prince Phillip and his many affairs, Princess Margaret - too many to count. The photo of PA with the underage girl has been in the tabloids before.
JMO, Epstein's murder was more about financial crimes and power than a sex scandal, though both things were probably part of it. I'm still going with his blackmail activities among the wealthy and powerful. Billionaire oligarchs can survive a sex scandal, most people don't recognize their names or faces anyway. Rich people don't go to jail for those kinds of crimes, because the victims don't have the power to make it happen.
Epstein and pals would have a problem, though, if the other powerful people and countries they ripped off or defrauded learned about their crimes. Those people get revenge.