I had some ashy/swinhoe's minivets in higher Tai Tam (but no scarlet/grey-chinned), but these are migrants. Crested Serpent Eagle was heard a couple of times down Tai Tam as well. I don't think that the rarity of this raptor is linked to low density of snakes / lizards. These breed very healthily on the island, where they are less hunted than in the new territories (I have seen at least 10 species of snakes, on the island, and my record of bamboo vipers seen in one night was in Tai Tam, where I saw 10 along a single catchment).
