NASHVILLE—-Sebastian Williams-Adams admits that he was “close” to committing to Vanderbilt as a high schooler, before he chose to start his college career at Auburn under Bruce Pearl.  Williams-Adams says it was difficult to let each of the other three schools—Vanderbilt, Purdue and Oklahoma State—in his final four that he’d be heading elsewhere. Vanderbilt, he says, was especially difficult to say no to.  Multiple sources told Vandy on SI that Vanderbilt had a lucrative deal on the table to Williams-Adams, it planned to use him in a big role right away and Williams-Adams says Vanderbilt coach Mark Byington was always clearly high on him. Williams-Adams knew he let him down, though. It became an easier pill to swallow when he committed to Byington and company out of the transfer portal a week ago, but it weighed on him at the time.  “I felt like a s****y person for telling him no,” Williams-Adams told Vandy on SI.…