From what I understand through cursory Googling, trading in illegally-harvested timber is a federal crime in the United States [1], and it's a strict liability, meaning everyone in the chain is subject to penalty via law enforcement. I don't know if unknowingly receiving illegal timber without penalty gives you standing to sue.
Yes but there is an intent component so only if they didn’t exercise “due care.” A consumer might be liable if they buy something obviously illegally harvested like Cuban mahogany (unless it’s very old stock that predates the ban) from some rando on Craigslist but if they’re buying wood from a lumberyard or hardware store, they’re likely in the clear (IANAL).
If the feds are going after end users those same feds can't be trusted to use good judgement regarding the definition of "due care". Nobody wants to ruin their life being "right" in federal court hence people keep their mouths shut.
Often times it isn't as that can be abused by bad actors that attempt to insulate themselves from liability by foisting it off on others. I think in a lot of cases markers of intent may be useful here - if you specifically request a class or species of wood that is restricted in logging you'd likely be held liable - "Oh I had assumed this specific rare tropical wood would be ethically sourced"... while as if you'd just requested a hardwood and contractor happened to source an illegally sourced wood the liability would likely be lessened.
In this particular case it's actually particle board so end customers were likely completely unaware it was illegally sourced.
If I were on a federal jury attempting to convict a home owner that had no direct knowledge of where the raw materials were sourced from, there's no way in hell I'd vote guilty.
Which has the wonderful side effect of creating backlog of "we found no intent so we just kinda dropped the matter and didn't bring charges" cases waiting to be prosecuted when some careerist decides they're only N cases way from some milestone and is willing to ruin lives to do it.
I know a guy who got screwed over something like that.
[1]: https://en.wikipedia.org/wiki/Lacey_Act_of_1900