Re your Point 2a, FF:

There are some fascinating, and very sad, descriptions of "feral" children, who were raised from infancy without exposure to language, and the evidence suggests that they are subsequently unable to acquire language skills, particularly in the area of grammatical structure. Francois Truffaut deals with one such case in his film "The Wild Child." Another instance concerns a girl named Genie, whose parents confined her to a room in their house, with no exposure to socialization or language. Several articles and books have been written about Genie. A number of them are referenced in Google if you search for Genie + feral. (I tried to list them here, but they didn't open (?)