If you haven't yet, create an account on pedigree database (free).
When you're logged in, you can look at the "history of changes" on any dog's pedigree, which will show you the username of the person who entered the dog and any subsequent title/health updates. You can send PMs to users. I would send messages to the full siblings Jax linked above and any other related dogs you can find.
It's a long shot, but at least those are people who definitely are/were involved with those actual dogs.
Last edited by WIBackpacker; 05-17-2019 at 11:38 AM.