I don't care what weapon you use. It's virtually impossible to remove three adults from a house unwillingly and leave the scene looking like they just walked away. Even surprising them in the house would likely leave something askew. There's that first moment before everyone is under control where things happen. People drop what hey are holding. They attempt to fend off the intruder. They bump things when herded out of the house. And all we have it a broken light globe?What is being "staged"? Why would there be a need? They didn't clean up the glass on the porch from the light. There was, as I recall, some stuff out of place in the area of Sherrill's closet, but that is not unusual or suggestive of staging. There was a blind that had a slat out of place. The TV was on, showing static. So why would someone do those things? It's not like they pointed to 3 runaway or to a burglary. Moreover, we have no real idea of what Stacy's mother and the rest of the unfortunate visitors moved, or "fixed," other than the broken glass.
People stage crimes to throw LE off, usually to disguise the acts of a criminal close to the victims. So they "stage" a burglary, usually. Or stage a domestic violence homicide to look like a psycho rapists did it. There's nothing in the appearance of the house that would either suggest or eliminate relatives of any of the three or for that matter, friends. The scene says nothing. The best "read" on that is an organized serial offender or offenders smart enough to leave no real evidence--or lucky because the "friends and family" event eliminated all of that.
I really believe the house was staged (a minor straightening up at least) or they weren't in the house when it happened (like they were lured outside). In the event of the McStay removal, there were signs in the house that pointed to a forced removal.