I think the idea with the iso file is a great one
you need to create an iso with the DRM unmodified (e.g. in Passkey this is the option 'Keep protection') and when you mount this iso in a virtual drive you can also use findvuk again to get the VUK and I think the validation should be possible in this case also
I'm pretty sure that no virtual drive will support bus encryption - so this way it should always be possible to validate the vuk
Another option to validate the vuk yourself would be to simply use a bluray player that uses the keydb.cfg file and takes care of the bus encryption.
Basically libaacs is capable of handling the bus encryption - but it always failed for me - eventually it needs a valid processing key for the encryption? So I think it's not possible to handle the bus encryption with only the VUK and this is the reason why there's no support for it in FindVUK...
But I've found something interesting in your logfile: the meta-title for 'Night at the museum 3' ends with a linebreak... strange thing
Eventually this line break is now also present in the keydb.cfg and might render this particular entry unuseable... (this might be the reason for your problems in linux?) - in case there's a linebreak in this line please remove it - I will improve the findvuk code for meta-title handling so that linebreaks are removed automatically...
And I think it would be a good thing to write the model of the drive also to the logfile...shouldn't be that hard to get this detail..