Looking for information on old Veder/Vanderbilt Family Cemetery plot from historic Underground Railroad home near Albany, NY?

Hi!

I am investigating the possible destruction of an old historic family cemetery with headstones at 6030 Nott Rd, in Guilderland, NY (5 min away from Albany). This historic home is said to have been part of the Underground Railroad. We were told that there are hidden doors/rooms in the house from during that time. The house was built around 1800, and was owned by the Veder Family, and possibly a member of the Vanderbilt family as well. The family cemetery in the back had headstones with those last names, including several small children/babies until the new owner destroyed them last fall, as part of an initiative to turn this beautiful historic property into a rental property.

I'm looking for guidance on how to prove that there was a cemetery there with headstones (the new owner says there were no headstones b/c removing them would
have been illegal, but we know he did), without actual photos. Does the Veder or Vanderbuilt family have any documentation on family cemeteries that has already been researched, and where could i find them? To be honest, I'm not even sure how to start researching this! The historical preservation society in Albany has been engaged, is looking into this, but I have a feeling I may need to do some leg work to get this done before the new owner destroys anything else.

Thanks in advance!
Melissa