I personally think the white powder hoax letter complaint is currently in front of a federal grand jury, being evaluated for charges. (Those proceedings are always secret.) This letter was taken very seriously-- a full Hazmat response, etc. Diversion of emergency resources, emotional distress, chaos at the workplace, diversion of FBI resources, etc. Not a victimless crime.
IMO, there is no way he won't face some federal charges for the white powder letter. He "could" also be facing separate federal civil rights/ hate crime charges stemming from the political and racial aspects of his state crime hoax (blaming it on MAGA-hatted white attackers, etc.)
"White powder letters" are very serious crimes, and are taken very seriously. Numerous individuals have received prison time, in addition to huge fines ($50,000+).
Federal penalties are up to 5 years in prison, and up to $250K fines/ restitution. I got more than 8 million hits when I used a search engine to look at "white powder letters crimes".
JS may likely plead the 16 state felonies down to 1-4 years of jail time, followed by lengthy parole. But
when (not "if") the federal charges drop, he's looking at real time. He will be re-arrested, have separate arraignment, have separate hearings, separate trial (if no plea), and separate sentencing. (IMO.)
Sentences won't run concurrently, because the charges will be separate crimes (state and federal). They literally "can't" consider the crimes together-- the letter is a separate federal crime from the state hoax charges. And....he's gonna need TWO separate teams of attorneys, IMO-- for a lengthy period of time (1-2 years) leading up to sentencing. That won't come cheap.
Meanwhile, he will be "cancelled" by Hollywood, and won't get any work. In a few days to weeks, he'll be let go from his current contract, IMO, and no one will pick him up with charges and sentencing pending. Actors (esp ones with troubled legal and substance abuse histories) often need insurance coverage to obtain their contracts in the performing arts industries, to protect the investment and "product" (TV show, music, etc) of the contract grantor-- and what insurance company will insure him in these tangled circumstances?? Attorney fees (high profile celebrity attorneys) will quickly bankrupt him.
Some interesting articles on "white powder letter" crimes and hoaxes.
White Powder Scares Cost Law Enforcement Time, Money
Is It a Crime to Mail White Powder Even If It's Harmless?
How Fake Bioterrorism Attacks Became a Real Problem