Is translating a Terry Pratchett novel from English to Czech a creative endeavor?
You can argue that on some level, yes, any translation is creative. But I don't think it's the same as writing an original novel (even if the result is bad). On some level, it's decidedly non-creative (and that's what the GP asked about), because you already have the characters, the story, the words. And apparently, some people are fine with already having all that. (It's even not deemed creative enough to be considered different for the copyright.)
Is coloring a coloring-book creative? Compared to making your own drawings?
Is coloring creative? I think that's a different question from whether a complete, clean re-implementation of a software library is creative.
As for that question though, I'll push it a bit further - is drawing an outline of a bird creative? I'd argue it's more interesting than the next person coloring the bird. But it's also decidedly less interesting that what evolution has done in generating a bird from billions of years of evolution.
But I'd say yeah, something was created because the artist had a desire for the bird, and then produced it. Or, the artist (for some definition) had a desire for a green bird, then colored it. Of course, neither the drawing of the bird nor the coloring was novel.
So as it's not an autonomous manufacturing process, it's creative. Your bones generating blood cells is not creative work.
Software that adds colors between lines isn't itself creative, but the person who developed the software used creativity.
You can argue that on some level, yes, any translation is creative. But I don't think it's the same as writing an original novel (even if the result is bad). On some level, it's decidedly non-creative (and that's what the GP asked about), because you already have the characters, the story, the words. And apparently, some people are fine with already having all that. (It's even not deemed creative enough to be considered different for the copyright.)
Is coloring a coloring-book creative? Compared to making your own drawings?