Ending question (spoilers)

They buddied up with the police officer after helping him, so one can imagine he writes it down as “natural” causes?... and I assume an autopsy woul-operate .

Hehe. I came here to mention the same thing. The father is in the house with his throat slit. The daughter is in an underground cave system mangled. Ed and Lorraine are the only ones that make it out alive. Also, if you don't believe in the whole astral projection crap that Lorraine claims she has, then her knowing where Katie died in the woods and the location of Jessica's body would also point suspicion towards her and Ed.

Insidious 2 was the only horror movie I can remember that ever took care of the "How do we explain this to the police question." Because this is the ending of so many horror movies lol.