Perhaps you are an attorney. I am not although I've had long-term friendships with a few attorneys so I have had many "free-wheeling" discussions with "legal eagles." You could very well be right but based on my decidedly non-professional legal opinion, I'd be surprised if it would work out the way you've suggested. Here are some areas in particular I wonder about.
1. I seriously doubt anyone who did not lie to LE but merely failed to report his/her secondhand knowledge of the disposal of HP's body would be liable anywhere, for anything (you seem to suggest liability for anyone with knowledge.) In general Americans aren't required to volunteer information to LE. And if intentional infliction of emotional distress forms the basis for the civil suit, I'm not an all sure that Person A failing to call the police despite believing Person B disposed of HP's body makes Person A liable.
2. I'm not sure what the management of the H&F has or hasn't done. It was reported they required a search warrant to access security video. That made perfect sense. And I can't believe the LAPD wouldn't have known that. (If nothing else, checking the boxes makes sense in case of a criminal trial.) So I take what's reported about the management with a grain of salt and am not sure about liability.
3. While cases can be taken on contingency, to me this case sounds pretty iffy if it's about HP's body and her body can't be found. Attorneys generally take contingency cases that are pretty sure wins. Cases that are iffy AND have upfront costs? For example, taking depositions costs money. (I believe a court reporter or someone with those skills would be needed, for example. That costs money that
someone has to pay upfront.)
4. While there has been plenty of "gossip" about the trash chute in the tabloids and apparently on SM, and there must be some reason LE is searching the landfill, I don't think any of us know if there's actual evidence HP was dumped in the trash chute.
5. While "big money" pre-trial settlements sometimes are forthcoming in civil suits, particularly when corporations with deep pockets are involved, I'm not so sure a bunch of drug users will react the same way and pay up (if indeed the dumping occurred after drug use.) So a trial could be required.
6. I go back and forth in my mind about what LE knows. Sometimes I think they know alot (as you've suggested they do.) Other times I'm not so sure. I think they know she's dead but other than that? For example, in this video report supposedly a "LE source" admitted they know very little about what happened. That it's still a mystery.
Police Search Landfill North of Los Angeles in Disappearance of West LA Woman Heidi Planck
7. While some private info about HP has been released, I do think it could potentially get worse in court. So trying to "get justice" for the disposal of HP's body by winning money in court might not be in the best interests of BW.
But we'll see, I guess.
JMO