This sounds great! The ideal solution would be a script (for the sake of transparency) doing the merging of the entries for the pilots into the LOD0 file, so that you can do this with any futur update more easily.
I believe you’re talking about this post in particular isn’t it?
Visible co-pilot in first person view - #17 by CptLucky8
[edited - nonsense]
Can you confirm you’re adding the json entries but there are no additional references to the indices and vertices data arrays (which are in fact the equivalent of the index and vertex buffers in the 3D API), unlike the other parts of the model where these are embedded in the accompanying .bin file(s)?
The next step will ne to spawn a few more in passenger seats. This should give good results in the CRJ and the K350, but It might be not possible we can’t get different passenger types.