So they took Branwen's origin story and gave it to Minsc, huh?
I believe that petrified Minsc isn't Larians doing but was in lore before BG3 (vague hearsay - I don't know BG-related products outside main games)
Long story short: Minsc and Boo were petrified right after the Bhaalspawn saga, exposed as a golden statue in Baldur's Gate for like a hundred years, unpetrified accidently by a wild mage and resumed his adventures. Meanwhile, his "statue" was replaced with a REAL statue without anyone knowing.