This all is a total no-go zone. There seems to be confusion here between cases filed in SDNY (state crimes) and the federal investigation (federal/international crime).
The federal investigation is being conducted into the criminal activity of sex trafficking minors which is where Andrew would come in *voluntarily* submitting to being interviewed as to "what he knows". There is absolutely *no one* looking to charge Andrew with any sort of a crime at this time. They don't care if he was at Pizza Express or if he was sweating buckets at Tramps or anything of the sort. They're looking for assistance that would aid them to find, arrest and prosecute those that aided and abetted Epstein in his sex trafficking crimes.
SDNY, while being a federal judicial court, only prosecutes crimes within its jurisdiction which include New York (Manhattan), Bronx, Westchester, Putnam, Rockland, Orange, Dutchess, and Sullivan in the state of New York. Unless Andrew committed a crime in their jurisdiction, they would have no reason to be interested in Andrew at all other than as a witness to a crime, information that would lead to the conviction of a crime in their jurisdiction or help them nab people of interest they're looking for that *are* suspected of criminal activity.
Anything Andrew gives to any investigation at this time would be strictly *voluntary*. He did state that he would be willing to assist if asked to and it does seem like he's reneging on his word and not cooperating but that's solely within his rights to do at this time.