XDEV isn't part of the talk as that's external production (and only Kazuma Kizuka and Edward Saito moved there).
I only know of Shunan Sukawa (animator) and Toshitake Tsuchikura (lead programmer) from the development team that remained at Team Asobi.
There's obviously a lot of general Japan Studio staff that are still at SIEJ, but I'm specifically talking about the Demon's Souls development team here.
XDEV's -a.k.a. External Development- Japanese team (previously inside Japan Studio since they merged) is the one who handled games like Demon's Souls, Bloodborne, Demon's Souls Remake or more recently -after the restructuring- Death Stranding Director's Cut, Stellar Blade, Rise of the Ronin, Lost Soul Aside, Convallaria, Death Stranding 2 or Physint.
They continue doing the same job than before in the same building they were before: the Japanese SIE HQ building. But in a newer office because now they also handle the games from the rest of Asia, not only the Japanese ones.
In Moby Games you can double check who worked both in Demon's Souls remake and in Astro Bot, Stellar Blade or Rise of the Ronin.
Demon's Soul's remake was developed and published before the Bluepoint acquisition, so it was a 2nd party game, so handled by XDEV, like the other games I mentioned. Even if as usual there's someone from the internal development teams supporting these games. As happened multiple times in Japan Studio, or in Santa Monica when they still had the American XDEV team inside their studio, or in Liverpool Studio when they still had the European XDEV team inside their studio.