Six members of the same family, including three children, who were unaccounted for after a massive house fire and shooting in the Philadelphia suburb of East Lansdowne are now presumed dead, authorities said Thursday. Two police officers — identified as 54-year-old David Schiazza and 44-year-old John Meehan — were also wounded by gunfire, but are currently in stable condition. They have each been with the East Lansdowne Police force for more than 20 years. The incident began at around 3:45 p.m. Wednesday when Lansdowne Police received a call regarding the potential shooting of an 11-year-old g…