We actually work on LIGO's seismic isolation, too. We are adapting some of what we know from that work to improve our own isolation systems. Torsion balances have slightly different requirements, so it's not just drop-in use of that technology, but it is pretty close.

Regarding van der Waals -- yes. At the moment, we block all electrostatic/Casimir interactions with a metal foil. When the distances involved are "sufficiently short", we won't get complete screening any more. That day will be an interesting day.

On the bright side, if we start to see Casimir leakage, that will be a boon to the people who try to understand the Casimir force at finite temperature (another open problem), so we'll learn something useful no matter what...

In the short term, though, I'd love to have that problem. It will take a lot of work for us to get there.