There's at least a very faithful mod conversion of the game for PC, though I'm not sure it jives well with Bethesda's policies on content taken from other games.
It wouldn't matter what Bethesda's policies were since Beth is just a sister house to Id Software
Removing content from a game to be used in another is illegal regardless of who it is unless you have permission to do it. Some developers and publishers may be more open to this but I know id software has closed down projects that did this in the past.
Do you know if Bethesda/Zenimax isnt the owner?
No, but I don't see why id would own an IP made by another developer. Chances are Raven owned the IP, which means it is now Activision's - it's even possible that Activision had it from the start as they were the games' publisher.
If id did own these I wouldn't be terribly be surprised but I do believe Raven/Activision is the more likely owner.