cannot sign a NLI (national letter of intent) until November. The NLI is binding, but the verbal commitment can be reneged upon like Jenna Brown did this past year. If you change your mind after the NLI is signed, you have to sit out a year before you can play for your new team.
So Sam and Anaya will sign their NLI in November 2018 along with anyone else that Notre Dame gets this recruiting season.