No one devised a scheme to frame Karen that night and I don't know anyone who thinks that's what happened.
JO wasn't hit by a car. But he was - at some point before daylight - put out on the lawn to make it appear a passing motor vehicle struck him. They'd have been happy to pin it on poor Lucky. (And I think he knows that now.)
They didn't know Read had a cracked taillight. Cracked just a little while before when she'd hit John's car. Must have seemed a god send to them at the time, not knowing it was all caught on video.
Read contacted Jen that morning because she'd dropped John off at Jen's sister's house the night before at Jen's invite. She didn't know the Alberts personally and only had Jen's number. What happened at that party??? Where was John?? Jen called her sister Nicole (they both deny this call, but it's confirmed in the phone records) to warn her that Karen wanted to go to Fairview, as Jen had told Karen that John never came into the house despite the fact that Karen dropped him off there. Jen tried to control the situation by agreeing to get Kerry and go to Fairview. After suggesting they try other places first.
Had Karen not turned up with a cracked taillight, I see no chance of her being directly framed. Or charged for that matter.