There are so many areas of human ontogeny being explored for possible heterochronic mechanisms of evolution. One problem with this area of research is the mess that has engulfed the terminology and hence the analysis of data - as is evident in how McNamara deals with brain evolution. Even the bonobo has often been labelled as neotenic relative to the common chimpanzee, but this too seems false. While I havn't researched any area in depth apart from cranial and brain "neoteny", I can add that neoteny is likely to be fairly rare. As I described in that argument, neoteny requires a shift towards isometric growth, which requires positive allometries to "flatten" towards isometry and negative allometries to "steepen" towards isometry. This combination seems unlikely to occur often in evolution. I'm afraid I cannot make any more informed comments in regards to your questions, because I'm simply not knowledgable enough about other people's research in those areas!
"Hairlessness" in humans is generally considered a heat adaptation. Humans have unique sweat glands that are considered a specific adaptation to the environment they evolved in, we can sweat far more efficiently and to a higher degree than any other animal (due to unique sweat glands). I remember reading somewhere that a human could survive ambiant temperatures of 120C if provided with enough water and conditions allowing rapid evaporation of sweat (don't take that as gospel, it's just a memory). However, humans have not lost hair as such, our body hair is simply very small but we still retain roughly the same number of hairs. It would seem more likely that some genetic adaptations suppress extensive hair growth, which could explain why some individuals can be covered in full body hair. I would be sceptical of labelling things as neotenic based on apparent similarities with juvenile apes. But again, I'd have to look at genuine research. Sorry I can't shed more light on your queries
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