I experimented with cyanotypes in a pinhole several years ago, with very limited results.
Cyanotypes are not just slow, but they are very specific in regards to the wavelengths of light to which they respond. Correct me if I'm wrong, but I believe cyanotypes work through the transmission of UV light, that is, the amount of UV that reaches the paper through your negative or whatever is covering your paper. When we view a scene, we are seeing the visible wavelengths of light, not the UV. Your subject may reflect
some UV light, but not enough to create a satisfactory image, particularly given the low ISO of the paper and the high f-stop of your pinhole. Now, as to how much UV the elements of a given scene would reflect or absorb, who knows? (certainly not me).
When I tried pinhole cyanotypes, I left my camera in place for several bright summer days, and the best I could optimistically say is that there was "something" there. Granted, when I tried this, my pinhole was a pretty poor excuse for a camera; your experiments might happily prove me wrong.