Doesnt have to be a professional, someone known to the family would have had an idea of their routines and properties, i dont think it was a single person either.
If the shots were heard just before sunrise i wonder if B was supposed to have been a victim also?.
The operation would need several people - teams to go to different locations, others to look out for cars, witnesses, listening to police scanners.
The time frame was between around 11:30 pm (when Dana got home from work) to just before sunrise around 5:30 - 6 am.
It was a Friday night, so, unlike a weeknight, people in the Piketon area and in the Union Hill neighborhood were probably out and about til late. Cars driving around as people visited with each other, went to bars or to party, going to the store to pick up beer, smokes, diapers and snacks; turkey hunters coming in, setting up to hunt in early morning.
IMO, the killers would wait until well after the bars had closed to avoid being seen by those heading home after a few beers. That would give them from around 2:30 or 3:00 am until around 5:00 am - when turkey hunters set up.
That's only about 2 hours, not a lot of time to break into 4 different homes (located 8 miles apart) disable or distract a dozen or more guard dogs, remove/disable many surveillance cameras, kill 8 people, clean up the scene and leave.
Just wondering, how long would it take to do all of this at just one home:
Hide car and approach on foot
Search outside premises to make sure no one else is around
disable or quiet a few dangerous dogs
enter residence undetected (forced or keyed entry)
locate up to 3 or 4 victims and disarm and kill them, before any can make a cell phone call or text
clean up scene - fingerprints, shell casings, etc.
locate and remove multiple security cameras
locate and take money or valuables (unknown at this time)
check for any witnesses outside and to see if any traffic is moving along the road, check police scanners
drive to next location and repeat 3 more times.