Is there any explanation on why only humans and animals do not remember previous life?
All the beings you mention as remembering past lives are spontaneously reborn (opapaatika), whereas humans and animals are either egg-born (aṇḍaja), womb-born (jalābuja), or moisture-born (saṃsedaja). Only spontaneously reborn beings are readily able to remember their past lives; most others have their past life memories repressed by the trauma and general coarseness of their rebirth.

I know this is all general Buddhist knowledge, but I can't find a reliable source from the original texts; if anyone knows of one, please feel free to put it in the comments.