What happens to Mathilda after the events of the film
Realistically speaking, it's unlikely that Mathilda's story will continue to remain a secret. After all, not only was there a shootout in broad daylight but the NYPD and DEA would be already investigating the personal belongings and other incriminating evidence related to Leon and Stansfield, giving them a solid idea as to what truly happened. And that's not getting into Leon's presence in a federal building as well as eyewitnesses such as the hotel manager, the taxi driver and the old lady who are already familiar with him as well as Mathilda and eventually learn what happened to their clientele by watching the news, so they would at least want to testify as to what happened. Benny too would also testify as to what happened, ostensibly to save face and try to make his boss look good but once the full details come out to the public, he would be charged with misconduct and sent to jail. Furthermore, the headmistress of Spenser School already knows her story and even if she were to not disclose it to anyone else, the public would eventually discover that Mathilda was in fact the apprentice to an Italian-American hitman after her family was killed by a gang of corrupt DEA agents and cops for the reasons mentioned above.
For Mathilda, she would be the center of attention for the American public in 1994 with her crazy yet true story of going on a path of revenge against the man who murdered her family with the help of a mob hitman. She would also be put under house arrest given her involvement in multiple mob hits. The only people allowed to visit her would be journalists interested in documenting her life story and they would publish it as a book, which in turn would likely get a film adaptation. Once she grows up, Mathilda would want to live a normal life and would choose to stay out of the spotlight, outside of participation in documentaries about her life. And she wouldn't marry anyone else but Leon for very obvious reasons.
As for Tony, since he was the handler and boss of Leon, he would be arrested once the police learn enough information about his associate as well as Mathilda and Stansfield. His restaurant would be shut down and his employees sent to jail along with him.
