With Dixson in the portal and Mingo back on the market, Brown has probably been promised a starting job at UNC.
Dixon committed to Arizona for a reported $2 million.
Matt Norlander reported that Mingo got hurt again recently and is expected to redshirt (he missed most of his senior season with injuries too.) This gives some context to the reports that Coach Malone moved on from Mingo. You don't want to spend millions on a kid who is too injured to play. I suspect Mingo was a desperation recruit for Hubert, and I can only imagine the reaction by the fans when they found out he was redshirting had Hubert kept his job.
I suspect your read is right and Brown has been offered a starting role at UNC. I saw an interesting tweet that really encapsulates the Mike Malone philosophy. The 4 UNC guards that entered the transfer portal were terrible at attacking the basket. I suspect Malone kicked them all to the curb for that reason.