Generally, not, AFAICT. State laws (in some cases, under a federal mandate requiring states to do so to receive federal funds) designate a variety of mandatory reporters (one of the most universal of which is health care providers), but there is no federal universal reporting mandate.
Ok but where is the evidence? I don't think the cops can just showup to Epstain's associates door and try to snatch confessions without evidence. They have lawyers. Why would they confess?
Flying to an island on his plane (even after everything we know about that has happened on that island residence) does not itself indicate any wrong doing -- they have to fond more evidence that links the threads together. If they charge or show their hands before they have enough it sets various clocks in motion that can harm the long term cases.
I have faith they are still working as many of these as they can looking for charges -- its only faith.