It has been my experience (and I have some), that gun magazine writers, and CUSTOM GUN SHOPS, made issues such as this one, FAR MORE COMPLICATED THAN NECESSARY. The facts are, the more you bolt on a shotgun, the more there is to hang on doorways, clothing, ect. A standard 870 Remington, or Mossberg 500 is all one needs.
When I taught civilian classes I always told them: As long as you know where your family is, STAY PUT. The gremlin is at the disadvantage. LET HIM, COME TO "YOU". Bumpin around in the house is a good way to walk into your own ambush.
Now there are other shotguns out there, and I am giving what I KNOW will work and have USED in real world application, and as I said, I PREFER "my own" 1100 Remington shotgun, but I built this gun up personally, and I KNOW it will work, because it has worked.
Everyone has to pick what they feel comfortable with, but taking your facts from magazine writers, and custom gun shops is gonna cost far more than necessary.
The hardest part of all of this, is pullin the trigger should an event actually happen. Trust me, it ain't as easy as it would seem, and I have seen "bad asses" that ended up not being. It's a hard thing to stand and fight when you realize you might not win. And I would caution everyone on the MYTH of "rackin the ole pump" will scare off the spook! IT WON'T! There are folks out there, for one reason, or the other, that this doesn't even slow down. Make sure your justified before you pull that shotgun. If he's already in your house, call the coroner's office. He should be sound asleep when they get there.