Brooklyn’s Court Street could soon resemble Third Avenue — not the one in the Borough of Churches, but rather the one on the other side of the East River, predicts Cushman & Wakefield retail specialist Diana Boutross. National chains are increasingly staking out locations along low-key Court Street, Boutross says — mostly near its Cadman Plaza northern end, but also south to the Gowanus Expressway. “The whole market down toward Carroll Gardens is going to resemble Third Avenue on the Upper East Side,” Boutross said.