Yeah, plus even if there was no conversation between the band/Warner and Jeff, the bridge between Jeff and LP was burnt decades ago, they don't want anything to do with him and haven't since Hybrid Theory. Some of their statements about him in interviews indicate as such. It's not like he'd really be losing anything by releasing it. Plus Jeff already confirmed that demos will be a part of the vault. Legality on some things are definitely questionable, but Jeff has a degree in entertainment law so he'd know better than I would.
And Two is another one that Jeff confirmed in an interview around the HT20 time as an outro to And One, otherwise I think it'll mostly be variants of tracks we already have: Mark versions of HT EP songs and Slip, pre-HT EP And One, Xero Instrumentals, and maybe the songs they did at NRG for Hybrid Theory that weren't on the album if they weren't scrapped early on. There's probably other demos we don't know about as well.