While your Dwaita/Adwaita dichotomy makes sense in terms of general concepts, it's too clear-cut, and ignores some intersections between Hinduism and Buddhism.

> So it is odd that the Tibetan monks in the movie will print names of "God".

As you pointed out, some sections of Hinduism follow Adwaita philosophy. In the same vein, even though Buddhism doesn't have a pantheon like mainstream Hinduism, it still retains lists of named Buddhas [1]. These lists are common in Buddhism (see also the list of bodhisattavas [2]) as well as the related and older Jainism [3].

I believe that the core of the Clarke story is based on the overall concept of these lists, probably simplifying the concept of a Buddha to "God" for Western audiences. The closest related concept I can think of is the Holy Trinity, and most people in the Western world would struggle to explain the difference between Unitarianism and Trinitarianism.

The filmmaker had a chance to correct Clarke's simplification, but probably hasn't studied the source material in enough detail to know or care.

----------------------------------------

[1] https://en.wikipedia.org/wiki/List_of_named_Buddhas

[2] https://en.wikipedia.org/wiki/List_of_bodhisattvas

[3] https://en.wikipedia.org/wiki/List_of_Tirthankaras