This is quite interesting. Unfortunately, there are no recent studies to back some of the claims made. Also, the correlation observed in the animal kingdom arose from the comparison of animals of different species, not the same species. Humans are of the same species.
Some of the arguments about height having some correlations with cancer could have been plausible assuming our body maintains the same cell division rate throughout our life cycle.
Exactly, Humans are of the same specie while the other animals mentioned are of different specie. I remember stating that since our genetic makeups are quite different and we are affected by lots of factors including physical, environmental and lifestyle, so the hypothesis of height and lifespan is still contradictory and further research need to be done so as to confirm any correlation between these two.