Brandon Copeland sat in the corner chair as the seller came walking into the middle of the open-stage set. Almost immediately, it felt like the NFL linebacker-slash-real estate investor was the point guard, trying to get the conversation going. On the new Netflix reality series Copeland is a part of, “Buy My House,” the 31-year-old’s personality is on full display. The show, which debuted Friday, is sort of like ‘Shark Tank,’ — the set even looks somewhat similar with the show’s four investors, Copeland, Redfin CEO Glenn Kelman, Corcoran CEO Pam Liebman and real estate mogul Danisha Wrightster in a semicircle around a carpet sitting in comfortable chairs — but…