One had to be following the Justice and Doom game, but Lionel had the Queens killed in an airplain crash. Remember the headline in the Pilot? It said Queen CEO missing? So, how would a 9 year old Lex kill them off? Also, Lex had little to no memories of the past that he blocked off due to how bad they were. He even blocked out that his mother killed Julian. I didn't even watch the show, but I do recall that Lex was about to kill Jason, but stopped, because Jason was going to tell him something about Clark, but LIONEL shot Jason before he could tell Lex. Somehow, Jason survived and came back to die by meteor shower (I still don't get that).
Lex did kill Patricia, but to say that he killed them all, is streching it.
Chloe was presumed dead after she was blown up in the safe house in the finale of the 3rd season and wasn't discovered to be alive until the 2nd epi of the 4th season (I think that was Gone).
