I have absolutely no idea what is or is not licensed for what usage by highend.

but the production company are correct to check these details - as are all end-users.
The use of copyrighted material with appropriate clearances is very important.

Image rights, and broadcast rights may or may not be available in some image libraries.

I suggest you email bobby_hale at highend.com with very very specific questions.

And if you dont get the answer you need, then dont use the library(s).

If you have any doubts at all - you might need to check the precise wording on image licenses with a lawyer who understands copyright and usage of images in the broadcast industries.